JPH1115031A - Optical distribution method and optical distribution device - Google Patents

Abstract

(57) Abstract: A serial signal light having a high bit rate of 1 Tbit / s or more can be directly and easily converted into a spatially one-dimensional or two-dimensional multi-channel parallel signal light. . SOLUTION: A linear optical switch 30 is arranged on the optical path of the signal light 1 at an angle of 45 ° with respect to the traveling direction of the signal light 1, and a control light 2 synchronized with the signal light 1 is perpendicular to the optical switch 30. Make it incident. The optical switch 30 transmits the signal light 1 with a transmittance of a predetermined value or more only at the moment when the control light 2 is irradiated. Thereby, the area W of the optical switch 30
From p, Wq, Wr, Ws, Wt, Wu, spatial position portions 1p, 1q, 1r, 1s, 1t, 1u of signal light pulses 1A, 1B, 1C, 1D, 1E, 1F, respectively.
Are output light pulses 3Ap, 3Bq, 3Cr, 3 respectively.
Cut out as Ds, 3Et, 3Fu. Optical switch 30
Alternatively, a phase conjugate light generation device can be used,
In that case, the intensity of the output light can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical distribution (optical demultiplex) method and apparatus used in an optical communication system or the like.

[0002]

2. Description of the Related Art On the transmitting side, multi-channel signal light is multiplexed into time-serial signal light and transmitted to an optical fiber transmission line, and on the receiving side, the multiplexed serial signal light is multi-channeled. In an optical communication system for distributing the signal light, Tbit / s corresponding to the increasing amount of information
In order to realize an ultra-high-speed optical communication network of the order of (Terabit / sec), methods of optical multiplexing (optical multiplexing) and optical distribution (optical demultiplexing) corresponding thereto have been studied.

[0003] Conventionally, as a method of distributing multiplexed serial signal light to multi-channel signal light, an “Opl
us E No. 187 (June 1995), page 73 and below, a phase shift method that changes the phase of signal light and a frequency shift method that changes the frequency (wavelength) of signal light are considered. .

A typical phase shift method uses a two-path interferometer utilizing the optical Kerr effect. The refractive index of a nonlinear optical medium inserted into one optical path of the two-path interferometer is determined by the following equation.
When the control light pulse is not input by changing the control light (gate light) synchronized with the multiplexed serial signal light, the signal light pulse at that time is output from one output port of the two-path interferometer, and the control is performed. When an optical pulse is input, the signal light pulse at that time is output from the other output port of the two-path interferometer.

In the frequency shift method, the frequency (wavelength) of multiplexed serial signal light is changed for each channel by a control light in a nonlinear optical medium, and the changed signal light is changed by a wavelength separation element to each channel. The signal light is spatially separated.

[0006]

However, the above-described phase shift method spatially separates a signal light pulse that coincides with the control light pulse temporally from a signal light pulse that does not coincide with the control light pulse in time. In order to obtain only two outputs and separate and obtain multi-channel signal light pulses, the above-described two-path interferometer is multi-stage (where N is the number of channels, (N
-1) The signal light and the control light must be changed in their directions with respect to the two-path interferometer of each stage, and one of them must be incident with a different time delay,
The optics become significantly more complex, the more channels there are, the more difficult it is to deal with, and the very advanced process technology required to have a precise time difference between the signal light or control light of each stage. .

In the above-described frequency shift method, output light of a plurality of channels can be collectively obtained by converting signal light into a different frequency (wavelength) for each channel at once in a nonlinear optical medium. In addition, as the number of channels increases, it becomes difficult to convert the signal light to a different frequency for each channel at a time, and thus there is a problem similar to the above-described phase shift method.

Further, the above-mentioned means that information is stored only in the direction of the time axis, and a temporally serial, spatially zero-dimensional signal light is converted into a spatially one-dimensional output light. However, the same signal light is spatially
There may be a need or demand for converting to dimensional output light.

For example, in optical transmission of image information, on the transmission side,
The parallel two-dimensional image information for m × n pixels is multiplexed with serial signal light and transmitted. On the receiving side, the multiplexed serial signal light is divided into m channels in one axis direction and orthogonal to the m channels. N-channels in one axis direction
If spatially separated into two-dimensional parallel signal light, m × n
A two-dimensional spatial light modulator or a two-dimensional C
It can be processed or detected directly by a CD array or the like.

However, in the conventional phase shift method or frequency shift method, the serial signal light multiplexed in this way is spatially converted into a two-dimensional parallel signal light.
It becomes even more difficult than in the case of converting into spatially one-dimensional parallel signal light as described above.

Accordingly, the present invention is capable of directly and easily converting a spatially high-bit-rate serial signal light of 1 Tbit / s or more into a one-dimensional or two-dimensional multi-channel parallel signal light. It is made possible.

[0012]

According to the optical distribution method of the present invention, an optical device having a predetermined width in one direction is arranged on an optical path of a signal light composed of an optical pulse train, and the signal light and the signal light are spread. Control light synchronized with this, so that both cross on the optical device, and span the predetermined width,
The light beams are respectively incident on the optical device, and output light pulses corresponding to different spatial position portions of different light pulses of the signal light are generated from different regions within the predetermined width of the optical device.

In this case, as in the invention of claim 3, as the optical device, an optical switch whose on / off state is switched depending on whether control light having a predetermined intensity or more is irradiated is used as the output light pulse. In addition, different spatial position portions of different light pulses of the signal light can be cut out.

Further, in this case, the control light is vertically incident on the optical switch as in the invention of claim 4,
A method in which the different regions of the optical switch are simultaneously turned on, and the signal light is obliquely incident on the optical switch, or the control light is obliquely incident on the optical switch as in the invention of claim 5. Then, the different regions of the optical switch may be sequentially turned on, and the signal light may be vertically incident on the optical switch.

Further, in this case, the optical switch is turned on only at the moment when the control light is irradiated, so that the signal light is transmitted at a transmittance of a predetermined value or more. Or like the invention of claim 7,
The optical switch, only at the moment when the control light is irradiated,
As the ON state, the signal light may be reflected at a reflectance equal to or higher than a predetermined value.

Alternatively, as in the invention of claim 8,
As the optical device, when the probe light as the signal light and the pump light as the control light are simultaneously irradiated,
A pulse that generates a phase conjugate light of the probe light can be used as the output light pulse.

Further, in this case, the first pump light, which is the control light, is vertically incident on the optical device from one surface side of the optical device, and the control light of the optical device is transmitted. A reflection mirror is arranged on the other surface side, and the pump light transmitted through the optical device from the one surface side is reflected by the reflection mirror, and as the second pump light, at the same time as the first pump light, A method may be employed in which light is perpendicularly incident on the optical device from the other surface side, and the probe light as the signal light is obliquely incident on the optical device simultaneously with the first and second pump lights.

Further, in this case, a wave plate is disposed between the optical device and the reflecting mirror to polarize the first and second pump lights with each other in a direction orthogonal to each other. It can be done.

In the optical distribution method according to the second aspect of the present invention, the optical device having a predetermined width in one direction and the other direction intersecting with the optical device is converted into a signal light composed of an optical pulse train,
Or, it is arranged so as to have a biaxial inclination with respect to the control light synchronized therewith, and the signal light and the control light intersect each other on the optical device, and each of the one direction and the other direction The optical devices are respectively incident on the optical device so as to extend over a predetermined width, and correspond to different spatial position portions of different light pulses of the signal light from different regions within the predetermined width in the one direction and the different width in the other direction of the optical device. The generated output light pulse is generated.

In this case, an optical switch is used as the optical device, as in the optical distribution method according to the first aspect of the present invention.
Alternatively, a device that generates phase conjugate light can be used.

[0021]

In the light distribution method according to the first aspect of the present invention, the control light simultaneously illuminates each area within a predetermined width of the optical device by defining an intersection angle and a synchronous relationship between the signal light and the control light. Or, by irradiating sequentially, each area is simultaneously or sequentially turned on or a phase conjugate light can be generated, and at that time, different spatial position portions of different light pulses of the signal light are turned on or generate phase conjugate light. The light is incident on the area that has been enabled.

Therefore, different spatial position portions of different optical pulses of signal light are cut out from different regions within a predetermined width of the optical device as output optical pulses, or corresponding to different spatial position portions of different optical pulses of signal light. An output light pulse is generated as phase conjugate light. Therefore, the multiplexed serial signal light is spatially converted into a one-dimensional parallel signal light.

In this case, for example, when the bit rate of the serial signal light is 1 Gbit / s (gigabit / second), the time interval (pulse interval) of the signal light pulse is 1 ns.
(Nanoseconds), and the spatial distance interval is 30 cm, which makes the above method unrealistically huge as a device.

However, for example, if the bit rate of the serial signal light is 1 Tbit / s, the time interval of the signal light pulse is 1 ps (picosecond), and the spatial distance interval is 3
00 μm = 0.03 cm. So, for example,
In the case where the signal light is incident on the optical device at an angle of 45 degrees and the control light is incident on the optical device perpendicularly, the spatial light of each region where the output light pulse within the predetermined width of the optical device is to be generated is generated. The distance interval is 424 μm, and the predetermined width of the optical device is 4.2 even when serial signal light is converted into one-dimensional parallel signal light of 100 channels.
It may be just over a cm

Therefore, according to the optical distribution method of the first aspect of the present invention, a serial signal light having a high bit rate of 1 Tbit / s or more can be directly, easily, and spatially converted into one.
It can be converted to multi-dimensional parallel signal light.

When a device that generates phase conjugate light is used as the optical device, the intensity of the phase conjugate light as the output light can be made larger than the intensity of the probe light, which is the signal light, and the intensity of the probe light can be increased. Therefore, the problem of light loss can be avoided, and the intensity of output light can be increased.

In the light distribution method according to the second aspect of the present invention, the tilt angle of the optical device with respect to the signal light or the control light in the two axial directions, the intersection angle between the signal light and the control light, and the synchronous relationship are defined. Thereby, the control light simultaneously or sequentially irradiates each area within a predetermined width in one direction and the other direction of the optical device, and simultaneously or sequentially turns each area on or in a state capable of generating phase conjugate light,
At that time, different spatial position portions of different optical pulses of the signal light are incident on the region where the ON state or the phase conjugate light can be generated.

Therefore, different spatial position portions of different light pulses of signal light are cut out as output light pulses from different regions within predetermined widths in one direction and the other direction of the optical device, respectively, or different light pulses of signal light are different from each other. Output light pulses corresponding to different spatial positions are generated as phase conjugate light. Therefore, the multiplexed serial signal light is spatially converted into a two-dimensional parallel signal light.

As apparent from the above description, the optical distribution method according to the first aspect of the present invention, for example, if the bit rate of the serial signal light is 1 Tbit / s,
Even when converting serial signal light into two-dimensional parallel signal light of 100 × 100 channels, the predetermined width in one direction and the other direction in the optical device may be about several cm.

Therefore, according to the optical distribution method of the second aspect of the present invention, a serial signal light having a high bit rate of 1 Tbit / s or more can be directly, easily, and spatially converted to a 2 bit signal.
It can be converted to multi-dimensional parallel signal light.

Further, similarly to the light distribution method according to the first aspect of the present invention, when a device that generates phase conjugate light is used as an optical device, the intensity of output light can be increased.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment in the case of using an optical switch] (When control light is vertically incident on a transmission optical switch)
FIG. 1 shows an embodiment of an optical distribution method and an optical distribution device according to the present invention, in which a transmission type optical switch is used, signal light is obliquely incident thereon, and control light is vertically incident thereon. .

The signal light 1 'transmitted through the optical waveguide 10 such as an optical fiber is, in the case of FIG.
Tbit / s and a pulse time interval of 1 ps.

The signal light 1 ′ transmitted through the optical waveguide 10
Is incident on an optical system 20 configured by combining lenses, and as light emitted from the optical system 20, the signal light pulses 1A to 1F of the respective channels whose wavefronts are widened in a plane direction perpendicular to the traveling direction. A signal light 1 consisting of a row is obtained. Since the time interval between the signal light pulses is 1 ps, the spatial distance interval is 300 μm.

On the optical path of the signal light 1, a linear optical switch 30 is arranged with its line direction inclined at 45 ° with respect to the traveling direction of the signal light 1. The optical switch 30 is formed of a non-linear optical material whose absorption coefficient (absorbance) changes depending on whether or not the control light 2 is irradiated, and has a short relaxation time. It is assumed that the signal light 1 is transmitted at a transmittance equal to or greater than a predetermined value, has a predetermined width W in the line direction, and the signal light 1 is incident on the optical switch 30 over the predetermined width W. Let it.

The optical switch 30 is set at 45 ° with respect to the signal light 1.
When N (the number of channels) = 6 as shown in the figure, the predetermined width W is equal to 5 which is the spatial distance interval of the signal light pulse.
It is assumed that the route is twice as strong.

The optical switch 30 is more practically shown in FIG.
As shown in FIG. 2 and described later, by selectively providing a light-shielding layer, the six regions Wp to Wu which do not overlap each other within the predetermined width W when N = 6 as shown in FIG. It is desirable to function as an optical shutter unit. This allows the optical switch 3 to be
Each output light pulse 3Ap ~ cut out from 0
3Fu has no spatial overlap with adjacent output light pulses.

Alternatively, on the optical path of the signal light 1 or the control light 2 to be described later, the respective output light pulses 3Ap to 3Ap
A filter may be arranged so that Fu has no spatial overlap between adjacent output light pulses. Also, if necessary, to improve wavelength selectivity and SN ratio,
An interference filter such as a dielectric multilayer film may be provided.

The signal light 1 'transmitted through the optical waveguide 10 travels in the same manner as the signal light 1 synchronized with the signal light 1 and includes one control light pulse 2a for each set of the signal light pulses 1A to 1F. The control light 2 has a wavefront spread in a plane direction perpendicular to the direction. Information indicating the beginning of a train of signal light pulses 1A to 1F is inserted into the signal light 1 ', and the control light 2 synchronized with the signal light 1 in a time relationship to be described later can be easily applied to the signal light 1 from this. Can be formed.

The control light 2 is incident on the optical switch 30 over a predetermined width W with its traveling direction perpendicular to the line direction of the optical switch 30. In the case of the figure, the control light 2 is made to enter the optical switch 30 from the emission side of the signal light 1, but may be made to enter the optical switch 30 from the incidence side of the signal light 1.

As will be described later, the signal light pulse 1A is obtained only from the region Wp, and the signal light pulse 1B is obtained only from the region Wq.
Thus, the time width of the control light pulse 2a is set so that the signal light pulses 1A to 1F are spatially separated and cut out only from the corresponding regions Wp to Wu of the optical switch 30. Regions Wp to Wu in the given wavefront direction
Wp to Wu of spatial position portions 1p to 1u corresponding to
Is sufficiently shorter than the difference in the time to reach the regions Wp to Wu due to the difference in the optical path lengths up to. That is, when the optical switch 30 is inclined at 45 ° with respect to the signal light 1 as shown in the figure, the time width of the control light pulse 2a is made sufficiently shorter than the time interval of the signal light pulse.

For example, if the time width of the signal light pulse is 100 fs (femtosecond), which is 1/10 of the time interval (1 ps), the time width of the control light pulse 2a is almost the same as that of the signal light pulse. It may be slightly shorter than that.

An optical processing element such as a spatial light modulator or a CCD is provided on the optical path of the signal light 1 on the front side of the optical switch 30.
A line-shaped or one-dimensional array-shaped optical element 40 composed of an optical detection element such as an array or a photodetector array,
The pixels are arranged so as to be located on the optical path of each spatial position portion 1p to 1u of the signal light 1.

In the method or apparatus described above, FIG.
As shown in (A), the control light pulse 2a is applied to the optical switch 3
Each of the 0 regions Wp to Wu is simultaneously illuminated and simultaneously set in a transmission state. Then, as shown in FIG.
When 1F simultaneously reaches the corresponding areas Wp to Wu of the optical switch 30, the control light pulse 2a is
The control light 2 is synchronized with the signal light 1 so as to reach the respective regions Wp to Wu.

Therefore, when the control light pulse 2a reaches each of the regions Wp to Wu of the optical switch 30, the spatial position portion 1p of the signal light pulse 1A corresponds to the region Wp, and the spatial position portion 1q of the signal light pulse 1B corresponds to the region Wp. Wq, the spatial position portion 1r of the signal light pulse 1C indicates the region Wr, and the signal light pulse 1C
The spatial position portion 1s of D divides the region Ws into the signal light pulse 1E
The spatial position portion 1t of the signal light pulse 1F passes through the region Wt, and the spatial position portion 1u of the signal light pulse 1F passes through the region Wu. As shown in FIG.
It is cut out as 3Bq, 3Cr, 3Ds, 3Et, 3Fu.

Then, the output light pulses 3Ap to 3Fu
Is processed or detected at the corresponding pixel of the optical element 40. Therefore, the signal light pulses 1A to 1A of each channel
F is extracted as one-dimensional parallel information.

Although a part is omitted in FIGS. 1 and 2A and 2B, the signal light 1 is a set of signal light pulses 1A to 1F that are serially continuous.
As shown in (C), a set of output light pulses 3Ap to 3Fu is cut out continuously. However, FIG. 3 shows the spatial positional relationship between the output light pulses 3Ap to 3Fu. In time, one set of the output light pulses 3Ap to 3Fu is cut out at the same time. After six times the time interval of the light pulse, the next set of output light pulses 3Ap to 3Fu is cut out at the same time.

Therefore, when N = 6, the optical element 4
Each pixel of 0 only needs to be able to process or detect the corresponding output light pulse 3Ap to 3Fu every six times the time interval of the signal light pulse. When the number N of channels is more practical, the optical element 40 may have a slower response speed, and has sufficient feasibility as a device.

As described above, according to the above-described embodiment, a serial signal light having a high bit rate of 1 Tbit / s or more can be directly and easily converted into a spatially one-dimensional multi-channel parallel signal light. Can be converted.

FIG. 3 shows another embodiment of the light distribution method and the light distribution device according to the present invention, in which a signal light is vertically incident on the transmission type optical switch. In this case, the signal light is made to enter vertically, and the control light is made to enter obliquely.

In this embodiment, the optical switch 30 is arranged on the optical path of the signal light 1 with its line direction perpendicular to the traveling direction of the signal light 1, and the signal switch 1 extends over a predetermined width W. Control light 2
Is made to enter the optical switch 30 over a predetermined width W with its traveling direction inclined with respect to the line direction of the optical switch 30. Others are the same as the embodiment of FIG.

However, as described later, the signal light pulse 1
The signal light pulses 1A to 1F are spatially separated and cut out only from the corresponding regions Wu to Wp of the optical switch 30 such that A is only from the region Wu, the signal light pulse 1B is only from the region Wt, and so on. As described above, the difference between the arrival time of the control light pulse 2a in the regions Wu to Wp due to the inclination of the spread wavefront of the control light 2 with respect to the optical switch 30 is made equal to the time interval of the signal light pulse, and The time width of 2a is made sufficiently shorter than the time interval of the signal light pulse.

In the method or apparatus described above, FIG.
As shown in (A), the signal light pulse 1A is
When the control light pulse 2a reaches 0, the optical switch 3
The control light 2 is synchronized with the signal light 1 so as to reach the area Wu of 0.

Therefore, as shown in the figure, when the signal light pulse 1A reaches the optical switch 30, the region Wu of the optical switch 30 is made to be in the transmitting state, and the signal light pulse 1A
4 (B) is transmitted through the region Wu.
As shown in (1), it is cut out as an output light pulse 3Au.

Next, as shown in FIG.
When B reaches the optical switch 30, the control light pulse 2a reaches the region Wt of the optical switch 30, the region Wt is made to be in a transmitting state, and the spatial position portion 1t of the signal light pulse 1B passes through the region Wt, As shown in FIG. 4C, it is cut out as an output light pulse 3Bt.

Next, as shown in FIG.
When C reaches the optical switch 30, the control light pulse 2a reaches the region Ws of the optical switch 30, the region Ws is made to be in a transmission state, and the spatial position portion 1s of the signal light pulse 1C passes through the region Ws, As shown in FIG. 3, it is cut out as an output light pulse 3Cs.

Hereinafter, similarly, in the embodiment of FIG.
Spatial position portion 1u of signal light pulse 1A, signal light pulse 1
The spatial position portion 1t of B, the spatial position portion 1s of the signal light pulse 1C, the spatial position portion 1r of the signal light pulse 1D, the spatial position portion 1q of the signal light pulse 1E, and the spatial position portion 1p of the signal light pulse 1F are respectively output. Light pulse 3Au, 3B
These are sequentially cut out as t, 3Cs, 3Dr, 3Eq, and 3Fp, and are sequentially processed or detected by the corresponding pixels of the optical element 40. Therefore, the signal light pulses 1A to 1F of each channel are extracted as one-dimensional parallel information.

Also in this embodiment, when N = 6, each pixel of the optical element 40 processes or detects the corresponding output light pulse 3Au to 3Fp every six times the time interval of the signal light pulse. If possible. Practical number of channels N
When the number is larger, the optical element 40 may have a slower response speed, and has sufficient feasibility as a device.

FIG. 5 shows still another embodiment of the light distribution method and the light distribution device according to the present invention, in which the control light is vertically incident on the reflection type optical switch. This is a case where the signal light is made to enter obliquely and the control light is made to enter vertically.

In this embodiment, similarly to the embodiment shown in FIG. 1, the optical switch 30 is arranged on the optical path of the signal light 1 by inclining the line direction of the optical switch 30 by 45 ° with respect to the traveling direction of the signal light 1. I do. However, in this case, the optical switch 30
Is formed of a non-linear optical material whose refractive index changes according to whether or not the control light 2 is irradiated and which has a short relaxation time. Is reflected at a reflectance equal to or higher than a predetermined value.

The optical switch 30 is more practically shown in FIG.
By selectively providing the reflective layer as shown in FIG. 5 and described later, the six regions Wp to Wu which do not overlap each other within the predetermined width W when N = 6 as shown in FIG. It is desirable to function as an effective switch unit. Thereby, each output optical pulse 3Ap cut out from the optical switch 30 as described later.
~ 3Fu has no spatial overlap with adjacent output light pulses.

Alternatively, on the optical path of the signal light 1 or the control light 2 to be described later, the output light pulses 3Ap to 3
A filter may be arranged so that Fu has no spatial overlap between adjacent output light pulses. Also, if necessary, to improve wavelength selectivity and SN ratio,
An interference filter such as a dielectric multilayer film may be provided.

The signal light 1 is applied to the reflection surface side of the optical switch 30.
At the same time, the control light 2 synchronized with the signal light 1 is caused to enter the optical switch 30 in a direction perpendicular to the line direction of the optical switch 30 from the reflection surface side of the optical switch 30 to the predetermined width W. Then, the light enters the optical switch 30.

Then, at the position after the signal light 1 is reflected by the optical switch 30, a linear or one-dimensional array of optical elements 40 is placed.
It is arranged to receive the reflected light of １1u.

The signal light pulses 1A to 1F are applied to the optical switch 30.
At the same time when the control light pulse 2a reaches the respective regions Wp to Wu of the optical switch 30 at the time when the control light 2 reaches the corresponding regions Wp to Wu at the same time, Others are the same as the embodiment of FIG.

Therefore, only in the difference between transmission and reflection, as in the embodiment of FIG. 1, the spatial position 1p of the signal light pulse 1A, the spatial position 1q of the signal light pulse 1B,
Spatial position portion 1r of signal light pulse 1C, signal light pulse 1
The spatial position portion 1s of D, the spatial position portion 1t of the signal light pulse 1E, and the spatial position portion 1u of the signal light pulse 1F are output light pulses 3Ap, 3Bq, 3Cr, 3Ds, 3 respectively.
Et, 3Fu is cut out and processed or detected by the corresponding pixel of the optical element 40.

FIG. 6 shows still another embodiment of the light distribution method and the light distribution device according to the present invention, in which the reflection type optical switch is used. (A) and (B) are diagrams when the signal light is vertically incident on the light and the control light is obliquely incident on the light, and FIGS.

In this embodiment, similarly to the embodiment of FIG. 3, the line direction of the optical switch 30 is perpendicular to the traveling direction of the signal light 1 and the optical switch 30 is arranged on the optical path of the signal light 1. However, the optical switch 30 is of a reflection type as in the embodiment of FIG. 5, and the signal light 1 is incident on the reflection surface side of the optical switch 30 via the half mirror 50, and the control light 2 is The optical switch 30
In the optical switch 30 from the reflection surface side of the optical switch 30.

Then, the optical element 40 is placed at a position after the signal light 1 is reflected by the optical switch 30 and further reflected by the half mirror 50, and each pixel of the optical element 40 is positioned at each spatial position 1 of the signal light 1.
It is arranged to receive the reflected light of u to 1p.

The optical switch 3 having the spread wavefront of the control light 2
The region Wu of the control light pulse 2a due to the inclination to 0
The difference in the arrival time at Wp is made equal to the time interval of the signal light pulse, and when the signal light pulse 1A reaches the optical switch 30, the control light pulse 2a is changed to the area Wu of the optical switch 30.
3 is the same as the embodiment of FIG. 3 except that the control light 2 is synchronized with the signal light 1 so as to reach.

Therefore, only in the difference between transmission and reflection, as in the embodiment of FIG. 3, the spatial position portion 1u of the signal light pulse 1A, the spatial position portion 1t of the signal light pulse 1B,
Spatial position portion 1s of signal light pulse 1C, signal light pulse 1
The spatial position portion 1r of D, the spatial position portion 1q of the signal light pulse 1E, and the spatial position portion 1p of the signal light pulse 1F are output light pulses 3Au, 3Bt, 3Cs, 3Dr, 3 respectively.
Eq, 3Fp is cut out and processed or detected by the corresponding pixel of the optical element 40.

Note that, without using the half mirror 50, as shown by the dashed line in FIG.
An angle may be provided between the signal light 1 incident on 0 and the output light 3 reflected from the optical switch 30.

[Embodiment using phase conjugate light]
FIG. 7 shows still another embodiment of the light distribution method and the light distribution device of the present invention, in which phase conjugate light is used.

As described above, it is necessary to spread the wavefront of the signal light in the plane direction perpendicular to the traveling direction. However, the intensity of signal light transmitted through an optical waveguide such as an optical fiber is limited by the input resistance of the optical waveguide, so that the intensity of the signal light having a widened wavefront cannot be increased significantly. Further, when a transmission type or reflection type optical switch is used as in each of the above-described embodiments, the output light obtained is weak due to light loss in the optical switch.

Therefore, in the embodiment of FIG. 7, the intensity of output light is increased by using an optical device that generates phase conjugate light instead of the optical switch.

(Principle) Generation of phase conjugate light is a phenomenon belonging to the third-order nonlinear optical effect. As shown in FIG. 9, the laser light from the laser light source 111 is transmitted to the beam splitter 1.
12 is transmitted, reflected by the beam splitter 113,
Further, the laser light is reflected by a mirror 114, is incident on one surface of a phase conjugate light generation device 90 made of a non-linear optical medium as described later as forward pump light Ef, and the laser light transmitted through the beam splitter 113 is reflected by the mirror 115. The laser light reflected by the beam splitter 112 is incident on the other surface of the phase conjugate light generation device 90 as the backward pump light Eb, and is reflected by the beam splitter 116.
And on one surface of the phase conjugate light generation device 90,
The light is made incident as the probe light Ep, and the photodetector 117 is arranged in a direction opposite to the traveling direction of the probe light Ep.

As described above, the phase conjugate light generation device 90
When two pump lights Ef and Eb having the same wavelength are made to face each other, and probe light Ep having the same wavelength as the pump lights Ef and Eb is made incident, the pump light Ef
f, Eb and the probe light Ep from the phase conjugate light generation device 90 only when irradiated with the probe light Ep.
The phase conjugate light Ec facing p is generated. In the case of FIG. 9, the phase conjugate light Ec is detected by the photodetector 117 via the beam splitter 116.

The phase conjugate light Ec is a time reversal wave of the probe light Ep, and has the same wavelength as the probe light Ep. Further, the intensities of the probe light Ep and the phase conjugate light Ec are smaller than the intensities of the pump lights Ef and Eb.

However, the amplitude Ac (0) of the phase conjugate light Ec on the exit surface of the phase conjugate light generation device 90 is the same as the amplitude Ap (0) of the pump light Ef, Eb on the incidence surface of the phase conjugate light generation device 90. Is proportional to the product of a constant α determined by the nonlinear optical medium constituting the phase conjugate light generating device 90, and the proportional constant is k, Ac (0) = k × α × Ap (0) (1) , The intensity of the phase conjugate light Ec is increased by increasing the intensity of the pump light Ef, Eb.
It can be greater than the strength of p.

Therefore, by using a phase conjugate light generating device in place of the optical switch and using the above-mentioned signal light as probe light and the control light as pump light, the intensity of the probe light which is a signal light with a widened wavefront is obtained. If the optical switch is not large, the intensity of the output light as the phase conjugate light can be increased, and the problem of light loss in an optical device such as when an optical switch is used can be avoided.

FIG. 9 shows a case where the phase conjugate light Ec is extracted through the beam splitter (half mirror) 116. In this case, only 50% of the phase conjugate light Ec generated from the phase conjugate light generation device 90 is extracted. Can not.

On the other hand, as shown in FIG. 10, one of the optical paths of the pump light Ef and Eb, for example, the pump light Eb
１ ／ wavelength plate 118 is inserted into the optical path of
When f and Eb are incident, the phase conjugate light generation device 90
The phase conjugate light Ec generated from becomes a polarization orthogonal to the probe light Ep.

Therefore, as shown in the figure, the polarization beam splitter 119 can be used to extract the phase conjugate light Ec, and almost 100% of the phase conjugate light Ec generated from the phase conjugate light generation device 90 can be extracted. The output light intensity can be further increased.

In order to use a phase conjugate light generating device instead of an optical switch, a nonlinear optical medium that generates and stops phase conjugate light at a response speed of 1 ps or less is required. As a material having a large third-order nonlinear optical effect and exhibiting such an ultra-high-speed response, there are a semiconductor fine particle dispersed glass or a metal fine particle dispersed glass, a polymer organic thin film, an organic crystal thin film, and an organic associated thin film. These materials are 1ps
Since it has the following response time and is easy to increase in area, it can be sufficiently used as a phase conjugate light generation device. Also, semiconductor multiple quantum wells (M
Some of them show an ultra-high-speed response such as QW), and they can be used.

(Embodiment) FIG. 7 shows a case where a phase conjugate light generating device is used, signal light as probe light is obliquely incident thereon, and control light as pump light is vertically incident thereon.

Although omitted in the figure, the signal light transmitted through an optical waveguide such as an optical fiber. In the case of the figure, the signal light of six channels is multiplexed serially in time from the signal light to the direction perpendicular to the traveling direction. The signal light 1 is obtained, which is composed of a train of signal light pulses 1A to 1F of each channel, whose wavefronts are spread in various plane directions.

On the optical path of the signal light 1, a line-shaped phase conjugate light generating device 90 is placed, and its line direction is changed to the signal light 1.
And the signal light 1 is made to enter the phase conjugate light generation device 90 as the probe light Ep through the polarization beam splitter 144 over a predetermined width W.

From the signal light transmitted through the above-described optical waveguide, the traveling direction is the same as that of the signal light 1 and is synchronized with the signal light 1 and includes one control light pulse 2a for each set of the signal light pulses 1A to 1F. The control light 2 whose wavefront is widened in a plane direction perpendicular to the control light 2 is formed.

The control light pulse 2a is transmitted to the backward pump light E
b, the traveling direction of the phase conjugate light generation device 90
Perpendicular to the line direction, and is incident on one surface of the phase conjugate light generation device 90 over a predetermined width W. Further, on the optical path of the control light pulse 2a transmitted through the phase conjugate light generation device 90, the １ ／ wavelength plate 135 and the mirror 1
36, the control light pulse 2a transmitted through the phase conjugate light generation device 90 is transmitted through the quarter-wave plate 135, reflected by the mirror 136, and further reflected by the quarter-wave plate 13
5 is again transmitted to form the forward pump light Ef having a polarization orthogonal to the backward pump light Eb, and the forward pump light Ef is applied to the phase conjugate light generating device 90 over a predetermined width W.
Incident on the other surface.

In this case, the forward pump light Ef and the backward pump light Eb simultaneously enter the phase conjugate light generating device 90, that is, one of the control light pulses 2a is used as the forward pump light Ef as the phase conjugate light generating device 90. At the time of incidence, the position of the mirror 136 is adjusted such that a certain subsequent one of the control light pulses 2a enters the phase conjugate light generation device 90 as backward pump light Eb.

The phase conjugate light generating device 90 is formed of the above-described nonlinear optical medium. More practically, by selectively providing a light shielding layer as described later, the phase conjugate light generating device 90 overlaps with each other within a predetermined width W. If N (the number of channels) = 6, as shown in the figure, six areas Wp to Wp
It is desirable that u function as independent phase conjugate light generating units. As a result, each output light pulse generated as a phase conjugate light from the phase conjugate light generation device 90 as described later has no spatial overlap with an adjacent output light pulse.

Alternatively, a filter is provided on the optical path of the signal light 1, the control light 2 or the output light 3 so that each output light pulse has no spatial overlap with an adjacent output light pulse. May be. Also, if necessary,
In order to improve the wavelength selectivity and the SN ratio, an interference filter such as a dielectric multilayer film may be provided.

As will be described later, the output light pulse corresponding to the signal light pulse 1A is output only from the region Wu.
The output light pulse corresponding to the signal light pulse 1A to 1F is output from the corresponding region Wu of the phase conjugate light generation device 90, for example, the output light pulse corresponding to B is only from the region Wt.
ＷWp, the time width of the control light pulse 2 a is set to the region Wu of the spatial position corresponding to the regions Wu to Wp in the direction of the spread wavefront of the signal light 1. Regions Wu-W due to differences in the optical path lengths up to Wp
p is sufficiently shorter than the difference in the arrival time to p.

The phase conjugate light Ec of the probe light Ep, which is the signal light 1, generated from the phase conjugate light generation device 90 and extracted by the polarization beam splitter 144.
On the optical path of the output light 3 as above, an optical element 40 such as a spatial light modulator or a linear or one-dimensional array of optical detecting elements such as a CCD array or a photodetector array is arranged.

In the method or apparatus described above, FIG.
As shown in (A), the forward pump light Ef and the backward pump light Eb are applied to the respective regions Wp to Wp of the phase conjugate light generation device 90.
Wu is irradiated at the same time, and the phase conjugate light can be generated at the same time. Then, as shown in FIG.
At the time when the signal light pulses 1A to 1F as p simultaneously reach the corresponding regions Wu to Wp of the phase conjugate light generation device 90, the forward pump light Ef and the backward pump light Eb are converted into the respective regions Wp of the phase conjugate light generation device 90. ＷWu, the forward pump light Ef and the backward pump light Eb, which are the control lights 2, are synchronized with the signal light 1 as the probe light Ep.

Therefore, the forward pump light Ef and the backward pump light Eb are applied to each region W of the phase conjugate light generating device 90.
At the time point when p to Wu is reached, as shown in FIG.
Output light pulses corresponding to spatial position portions 1u, 1t, 1s, 1r, 1q, 1p of signal light pulses 1A, 1B, 1C, 1D, 1E, 1F from regions Wu, Wt, Ws, Wr, Wq, Wp, respectively. 3Au, 3Bt, 3Cs, 3Dr,
3Eq and 3Fp are respectively generated as phase conjugate light Ec.

The output light pulses 3Au to 3Fp as the phase conjugate light Ec are supplied to the polarization beam splitter 14.
Via 4, it is processed or detected at the corresponding pixel of the optical element 40. Therefore, the signal light pulse 1 of each channel
A to 1F are extracted as one-dimensional parallel information.

Further, since the output light 3 is obtained as the phase conjugate light Ec of the probe light Ep as the signal light 1, the intensity of the output light 3 can be increased as described above. Since the phase conjugate light Ec becomes a polarization orthogonal to the probe light Ep, the output light 3 as the phase conjugate light Ec is transmitted to the polarization beam splitter 1.
44, and the intensity of the output light 3 can be further increased.

(Specific Example) FIG. 11 shows a specific example of the light distribution method and the light distribution device using the phase conjugate light as described above. However, it is for experiments.

The titanium sapphire laser 122 is excited by the output light of the argon laser 121, and a wavelength of 780 nm and a pulse time width of 1 are output from the titanium sapphire laser 122.
00 fs, pulse time interval 10 ns (repetition frequency 1
00 MHz).

The output light of the titanium sapphire laser 122 is transmitted through the beam splitter 123, multiplexed by the optical multiplexer 141, and
From 41, a signal light consisting of a pulse train having a pulse time width of 100 fs and a pulse time interval of 1 ps (repetition frequency of 1 THz) is obtained, this signal light is reflected by a mirror 142, and about 5 mmφ by a collimator / expander 143.
, And transmitted through the polarizing beam splitter 144,
The probe light Ep is incident on the phase conjugate light generation device 90 at an angle of 45 degrees.

The output light of the titanium sapphire laser 122 is reflected by the beam splitter 123 and supplied to the amplifier 124.
The YLF laser 125 is excited by the output light of the
The output light of the F laser 125 is supplied to the amplifier 124, and control light having an intensity of 80 μJ / pulse is obtained from the amplifier 124.

The control light from the amplifier 124 is sequentially reflected by mirrors 126, 127, 128, 129 and 131, expanded to about 5 mmφ by a collimator / expander 132, and further expanded to a cylindrical lens 13
The light is condensed in a line shape by 3 and is vertically incident on one surface of the phase conjugate light generation device 90 as backward pump light Eb.

Further, the control light transmitted through the phase conjugate light generating device 90 is passed through a cylindrical lens 134,
The light is reflected by the mirror 136 via the quarter-wave plate 135, and the reflected light is again condensed in a line by the cylindrical lens 134 via the quarter-wave plate 135, and the phase is converted to the forward pump light Ef. The light is perpendicularly incident on the other surface of the conjugate light generation device 90.

Thus, the phase conjugate light generation device 9
0, the backward pump light Eb is incident on one surface,
On the other surface, the forward pump light Ef having a polarization orthogonal to the backward pump light Eb is incident. In this case, when a certain control light pulse from the amplifier 124 is incident on the phase conjugate light generation device 90 as the forward pump light Ef, the subsequent control light pulse from the amplifier 124 is converted into the phase conjugate light as the backward pump light Eb. The positions of the mirrors 127, 128 and 136 are adjusted so as to be incident on the generating device 90. The forward pump light Ef and the backward pump light Eb are synchronized with the probe light Ep as described above with reference to FIGS.

As the phase conjugate light generating device 90, photonic glass was used. This is obtained by dispersing Bi ₂ O ₃ as fine metal particles in glass, and has a relatively large third-order nonlinear optical constant (9.3 × 10 ⁻¹² esu),
It has a response time of less than 200 fs. The thickness of the photonics glass is set to 20 μm, and the probe light Ep as the signal light is used.
In addition, it is sufficiently smaller than the spatial distance interval 30 μm corresponding to the pulse time width 100 fs of the pump light Ef, Eb as the control light. Further, the phase conjugate light generation device 90
Is a photonic glass with a mask and a diameter of 100
Ten μm circular phase conjugate light generating portions were arranged in a line in one direction.

Then, the phase conjugate light Ec generated from the phase conjugate light generation device 90 is transmitted to the polarization beam splitter 14.
4 and taken out by a CCD array 145 in which ten pixels are arranged in a line in one direction.

As a result, ten light outputs corresponding to the ten phase conjugate light generation units of the phase conjugate light generation device 90 are observed on the CCD array 145, and the optical multiplexer 1
It was confirmed that the signal light from 41 was demultiplexed by the control light from the amplifier 124. Moreover,
The intensity of the phase conjugate light Ec as the output light was 100% or more of the probe light Ep as the signal light, and it was confirmed that there was no light loss due to demultiplexing.

In this experiment, a wavelength of 780
Although the light of nm was used, the photonics glass used in the experiment does not show absorption even in the 1.55 μm band, so that it can be similarly used in the 1.55 μm band mainly used in optical communication.

[Embodiment of Optical Switch] (Embodiment of Transmission Optical Switch) FIG. 12 shows a transmission type optical switch suitable for use as an optical switch of an optical distribution method or an optical distribution device as shown in FIG. 1 or FIG. 1 illustrates one embodiment of an optical switch.

In this optical switch, a functional thin film 32 exhibiting saturable absorption on the order of femtoseconds is formed on a quartz substrate 31, and a light shielding layer 33 is formed on the functional thin film 32 by vapor deposition and etching of aluminum. The portions 34 formed in a predetermined pattern and not covered by the light-shielding layer 33 of the functional thin film 32 function as a plurality of independent optical shutter portions.

The signal light 1 has a repetition frequency of 1 THz (pulse time interval of 1 ps) and a pulse time width of 100 fs, which is composed of a train of signal light pulses of 100 channels. $ 99,100
This transmission type optical switch was prototyped on the assumption that a 100-channel signal light pulse indicated by is separated in parallel by the control light 2 having a repetition frequency of 10 GHz (pulse time interval of 100 ps) and a pulse time width of 100 fs.

In the case where the optical switch is inclined by 45 ° with respect to the signal light 1 and the control light 2 is vertically incident on the optical switch, the spatial distance between the signal light pulses is 300 μm. In order to correspond to the wavefronts of 100 signal light pulses, 100 circular light sources having a diameter of 100 μm were formed in a line at a pitch of 424 μm in one direction. The total length of the optical switch is just over 4.2 cm.

The production method actually performed will be described. Quartz substrate 3
For No. 1, after immersion in concentrated sulfuric acid for 24 hours, washed with running water and further ultrasonically washed with ultrapure water. The functional thin film 32 is made of an organic material such as AlPo in consideration of a large area.
-F (fluoro-aluminum phthalocyanine) was used.

AlPo-F has a wavelength of 600 to 800 nm.
And an incident light having a power density of 5 × 10 ⁹ W / cm ² causes an absorption change of 45%. Absorption recovery time is 5
At 50 fs, it has a sufficient function as an optical switch used in the light distribution method or light distribution device of the present invention.

This AlPo-F is placed on a quartz substrate 31
Vacuum deposition was performed at 50 degrees and 10 ^-6 Torr to form a 0.8 μm thick functional thin film 32. On this functional thin film 32, aluminum is vapor-deposited at 10 ⁻⁶ Torr to a thickness of 500 nm, and a normal etching using hydrochloric acid is performed to form a light-shielding layer 33 in a predetermined pattern. And 100 pitches were formed.

[0117] As the functional thin film 32, in addition to AlPO-F, [pi conjugated polymer such as polydiacetylene or polythiophene, dye aggregates such as squarylium, or the like can be used C ₆₀ films.

Further, the light-shielding layer 33 only has to block the transmission of light, so that it does not reflect light like aluminum but may absorb light sufficiently. Further, when a light-transmitting substrate such as the quartz substrate 31 is provided, the light-shielding layer 33 is not provided on the functional thin film 32 but on the side opposite to the surface of the light-transmitting substrate on which the functional thin film 32 is formed. It may be formed on a surface. In addition, a light-transmitting substrate is not required, and AlP
The light-shielding layer 33 may be provided only on one surface of the base layer made of a functional material such as o-F.

(Specific Example When Using Transmission Optical Switch) FIG. 13 shows a specific example of an optical distribution method and an optical distribution device using the above-described transmission optical switch. However, it is for experiments.

A pulse time width of 100 fs and an oscillation frequency of 82
MHz OPO (Optical Parametric Oscillator)
61, wavelength 620 nm, pulse time width 100 fs
The output light 5 of the optical multiplexer 62 is partially
, The repetition frequency 1 THz (pulse time interval 1p
s) As the signal light 1 having a pulse time width of 100 fs, the optical system 20 widens the wavefront in a plane direction perpendicular to the traveling direction and makes the light switch 30 enter the optical switch 30.

As shown in FIG. 12, the optical switch 30 includes an optical shutter 34 made of AlPo-F
The transmission type is arranged in a line in one direction, and the line direction is inclined by 45 ° with respect to the traveling direction of the signal light 1,
It is arranged on the optical path of the signal light 1.

The remainder of the output light 5 is delayed as the control light 2 by the optical delay means 63, condensed in a line by the cylindrical lens 64, and made to enter the optical switch 30 vertically. The light intensity of the output light 5 was 500 μJ, and by condensing the output light 5 with the cylindrical lens 64, sufficient light power as control light was obtained.

In front of the optical switch 30, a photodetector array 41 in which 100 pixels are arranged in a line in one direction is arranged, and each pixel corresponds to each optical shutter unit of the optical switch 30. As the photodetector array 41 is required to have a response speed of 10 GHz, an ultra-high-speed photodiode made of GaAs was used.

Then, the output signal 7 of the OPO 61 is delayed by the delay circuit 67 and supplied to the lock-in amplifier 68 as a trigger signal.
Is supplied to a lock-in amplifier 68, and the lock-in amplifier 68
The fluctuation component of the output signal 8 of No. 1 was detected, and the detected output was measured by the computer 70.

As a result, voltage fluctuations were simultaneously observed in the output signals of the 100 pixels of the photodetector array 41 only when the timing of irradiating the optical switch 30 with the signal light 1 and the control light 2 was matched. This is because the control light 2 causes the optical switch 30 of the optical switch 30 shown in FIG.
In this case, it is considered that the absorption of the functional thin film 32 made of AlPo-F is reduced and the transmitted light intensity is increased, and the increased amount appears as a voltage fluctuation in the output signals of 100 pixels of the photodetector array 41.

By repeating the above detection and measurement, the OPO61
By monitoring the output signal 8 of the photodetector array 41 in correspondence with the output signal 7 of the
It was confirmed that demultiplexing could be performed on output light of 100 channels of z.

As described above, in optical communication, mainly 1.
Signal light in the 55 μm band is used. Therefore, 1.55μ
An experiment similar to the above was performed using signal light closer to the m band.

FIG. 14 shows this case. The output light 5 having a wavelength of 1.55 μm and a pulse time width of 100 fs from the OPO 61 is output by the wavelength conversion element 65 to a wavelength of 775 nm.
m and output light 6 having a pulse time width of 100 fs. By extracting the second harmonic of the output light 5, the wavelength can be converted without changing the pulse time width.

As described above, the wavelength is converted to 775 nm because the AlPo-F forming the functional thin film 32 of the optical switch 30 shown in FIG.
This is because absorption is exhibited at 0 nm. Although the efficiency is lower than 620 nm in the case of FIG.
However, it can operate as an optical switch.

The wavelength 775n from the wavelength conversion element 65
The signal light 1 and the control light 2 were generated from the m output light 6 and the same experiment as in the case of FIG. 8 was performed. As a result, it was confirmed that the 1 THz signal light 1 from the optical multiplexer 62 could be demultiplexed into 100 GHz output light of 10 GHz each.

In the case of FIG. 13 or FIG. 14, the photodetector array 41 does not necessarily have to be disposed immediately in front of the optical switch 30. The spread of the diffracted light after passing through the optical shutter 34 shown in FIG.
The wavelength of the transmitted light lambda, diameter omega _o of the transmission portion, and wherein between the refractive index n of the transmission portion, when calculated according to θ = λ / πω _o n,
When λ = 620 nm and ω _o = 100 μm, θ is 0.1
° or less, which is extremely small. Therefore, if necessary, the optical switch 30 and the photodetector array 41
An optical device may be inserted between the device and the device to process the transmitted diffracted light.

(Embodiment of Reflective Optical Switch) FIG.
Shows an embodiment of a reflection type optical switch suitable for use as an optical switch of an optical distribution method or an optical distribution device as shown in FIG. 5 or FIG.

In this optical switch, the reflective layer 36 whose refractive index changes on the silicon substrate 35 depending on whether or not control light is irradiated and whose reflectivity changes by interference reflection is formed by a plurality of independent effective switches. It is formed as a part.

The signal light 1 has a repetition frequency of 1 THz (pulse time interval of 1 ps) and a pulse time width of 100 fs composed of a train of signal light pulses of 100 channels. A signal light pulse of 100 channels indicated by # 100 is generated at a repetition frequency of 1
This reflection type optical switch was prototyped on the assumption that it was separated in parallel by the control light 2 having 0 GHz (pulse time interval 100 ps) and pulse time width 100 fs.

In the case where the optical switch is inclined by 45 ° with respect to the signal light 1 and the control light 2 is vertically incident on the optical switch, the spatial distance between the signal light pulses is 300 μm. In order to correspond to the wavefronts of the signal light pulses, a circular one having a diameter of 100 μm
100 pieces were formed at a pitch of 4 μm and arranged in a line in one direction. The total length of the optical switch is just over 4.2 cm.

As the reflective layer 36, MQW (multiple quantum well) of low-temperature grown Be-doped strained InGaAs / InAlAs was used. The MQW has an operating time of 250 fs and an incident light having a wavelength of 1.535 μm and a light intensity of 10 pJ.
It responds at a repetition frequency of 20 GHz and has a sufficient function as an optical switch used in the light distribution method or light distribution device of the present invention.

However, other materials can be used for the reflection layer 36. The substrate is not limited to the silicon substrate 35, but may be made of another material as long as the substrate has a sufficiently low reflectance compared to the reflective layer 36.

(Specific Example When Using Reflective Optical Switch) FIG. 16 shows a specific example of an optical distribution method and an optical distribution device using the above-mentioned reflective optical switch. However, FIG.
3 and FIG.

The reflection layer 3 of the optical switch 30 shown in FIG.
6 is operable sufficiently in the 1.55 μm band mainly used in optical communication. In this case, the OPO 61 (pulse time width 100 f
s, oscillation frequency 82 MHz)
m, the output light 5 having a pulse time width of 100 fs
Repetition frequency 1 THz by optical multiplexer 62
The optical system 20 widens the wavefront in the direction perpendicular to the traveling direction as the signal light 1 having a pulse time interval of 1 ps and a pulse time width of 100 fs, and makes the signal switch 30 enter the optical switch 30.

As shown in FIG. 15, the optical switch 30 is of a reflection type in which 100 reflection layers 36 made of the above-described MQW are arranged in a line in one direction. The signal light 1 is inclined at 45 ° to the traveling direction.
On the optical path of

The output light 5 is also delayed as the control light 2 by the optical delay means 63, condensed in a line by the cylindrical lens 64, and made to enter the optical switch 30 vertically.

At the position where the signal light 1 is reflected from the optical switch 30, a photodetector array 41 in which 100 pixels are arranged in a line in one direction at an angle of 45 ° with respect to the optical switch 30 is arranged. Pixel of the optical switch 30
Corresponding to each reflective layer. As the photodetector array 41, an ultrahigh-speed photodiode made of GaAs was used as in the case of FIGS.

13 and 14, the output signal 7 of the OPO 61 is delayed by the delay circuit 67 and supplied to the lock-in amplifier 68 as a trigger signal, and the output signal 8 of the photodetector array 41 is output. ,
The lock-in amplifier 68
8, the fluctuation component of the output signal 8 of the photodetector array 41 was detected, and the detected output was measured by the computer 70.

As a result, voltage fluctuations were simultaneously observed in the output signals of the 100 pixels of the photodetector array 41 only when the timing of irradiating the optical switch 30 with the signal light 1 and the control light 2 was matched. This is because the control light 2 changes the refractive index of the above-described MQW reflecting layer 36 of the optical switch 30 shown in FIG. 15 of the optical switch 30, which breaks the buffering condition and increases the intensity of the reflected light from the reflecting layer 36. It is considered that the increased amount appeared as a voltage fluctuation in the output signals of 100 pixels of the photodetector array 41.

By repeating the above detection and measurement, the OPO61
By monitoring the output signal 8 of the photodetector array 41 in correspondence with the output signal 7 of the
It was confirmed that demultiplexing could be performed on output light of 100 channels of z.

[Embodiment for Converting to Two-Dimensional Parallel Signal Light] The present invention can also be applied to a case where serial signal light is spatially converted to two-dimensional parallel signal light.

In this case, for example, when an optical switch is used, as shown in FIG.
Are arranged so as to have two-dimensional inclinations with respect to the signal light 1 or the control light 2 with respect to the signal light 1 or the control light 2 as shown in FIG. Although omitted, the other control light or signal light is
For example, the light is vertically incident on the optical switch 30.

FIG. 18 shows an embodiment of a light distribution method and a light distribution device in this case, in which a transmission type optical switch is used, signal light is obliquely incident thereon, and control light is vertically incident thereon. Is the case.

The signal light 1 ′ transmitted through the optical waveguide 10 such as an optical fiber is made incident on an optical system 20 composed of a combination of lenses, and is emitted from the optical system 20 as a plane perpendicular to the traveling direction. The signal light 1 is obtained, which is composed of a train of signal light pulses of each channel, the wavefront of which is widened in the direction.

On the optical path of the signal light 1, optical switches 30 each having a predetermined width in one direction and another direction intersecting the same are arranged so as to be inclined in two axial directions with respect to the signal light 1. Then, the signal light 1 is transmitted to the optical switch 30,
The light is incident over a predetermined width in each of the one direction and the other direction.

As in the case of the one-dimensional case shown in FIG. 1 or FIG. 3, the optical switch 30 has a non-linear optical material whose absorption coefficient changes depending on whether or not the control light 2 is irradiated and whose relaxation time is short. And the signal light 1 is transmitted in a transmission state at a transmittance of a predetermined value or more only at the moment when the control light 2 is irradiated.

From the signal light 1 ′, one control light pulse for each signal light pulse of the number of channels (4 × 4 = 16 in the figure) is used. Similarly, the control light 2 whose wavefront is widened in the plane direction perpendicular to the traveling direction is formed, and the control light 2 is transmitted to the optical switch 3.
The light is incident on the optical switch 30 in a predetermined direction in one direction and the other direction in a direction perpendicular to 0.

Also in this case, the time width (pulse width) of the control light 2 is set so that each signal light pulse is spatially separated and cut out only from the corresponding area of the optical switch 30. The optical switch 3 according to the difference in the optical path length between the spatial position corresponding to each area of the optical switch 30 and each area of the optical switch 30 in the widened wavefront direction.
0 is sufficiently shorter than the difference between the arrival times at the respective regions.

An optical element 40 is arranged on the optical path of the signal light 1 on the front side of the optical switch 30. The light element 40 is a light processing element such as a spatial light modulator or a light detection element such as a CCD array or a photodetector array.
2 are arranged in a two-dimensional array, and each pixel 42 is made to correspond to each of the above spatial position portions of the signal light 1.

In the above-described method or apparatus, the control light pulse simultaneously irradiates each area of the optical switch 30 and simultaneously makes the area transparent. The tilt of the optical switch 30 in the biaxial direction with respect to the signal light 1 is determined so that the signal light pulses of the number of channels simultaneously reach the corresponding regions of the optical switch 30, and the signal light pulses of the number of channels are determined by The control light 2 is synchronized with the signal light 1 so that the control light pulse reaches each region of the optical switch 30 at the time when the light reaches the corresponding region of the switch 30 at the same time.

Therefore, the control light pulse is applied to the optical switch 3
0, the spatial positions of the signal light pulses corresponding to the number of channels are different from each other.
Are respectively transmitted, cut out as output light pulses 3 a, and processed or detected by the corresponding pixels of the optical element 40. Therefore, the signal light pulse of each channel is extracted as two-dimensional parallel information.

Also in this case, each output light pulse 3
It is desirable that a does not cause a spatial overlap between adjacent output light pulses. Therefore, as shown in FIG. 19, a filter 8 having transmission pixels 81 for individually separating output light pulses on the optical path of the signal light 1 or the control light 2.
It is preferable to arrange 0. Alternatively, the optical switch 30 may be formed by two-dimensionally arranging optical shutter units 34 independent of each other as shown in FIG. 12 in one direction and the other direction.

In the method or apparatus described above, the optical element 40
It is only necessary that each pixel 42 can process or detect the corresponding output light pulse every time the number of channels times the time interval of the signal light pulse. Therefore, when the bit rate of the signal light 1 is 1 Tbit / s and the pulse time interval is 1 ps, for example, when the signal light 1 is obtained by temporally serially multiplexing two-dimensional image information of 100 × 100 pixels. Means that each pixel 42 of the optical element 40 is 1 ps × 100 × 1
It is only necessary that a response can be made every 00 = 10 ns. Further, when the signal light 1 is obtained by multiplexing two-dimensional image information of 1000 × 1000 pixels, each pixel 4
2 may have a response time of 1 μs. Therefore, the optical element 40
For example, a light processing element such as a two-dimensional spatial light modulator using a liquid crystal or the like, or a light detection element such as a two-dimensional CCD array or a two-dimensional photodetector array, which is currently considered, can be used.

Further, the bit rate of the signal light 1 is 1 Tb.
Even when the signal light 1 is converted to a 100 × 100-channel two-dimensional parallel signal light with an it / s and a pulse time interval of 1 ps, for example, it is shown in the embodiment of FIG. 1 and shown in the transmission type optical switch of FIG. As is evident from the
The optical switch 30 may have a size of several square centimeters and has sufficient feasibility as a device.

As described above, according to the above-described embodiment, a serial signal light having a high bit rate of 1 Tbit / s or more can be directly and easily converted into a spatially two-dimensional multi-channel parallel signal light. Can be converted.

In contrast to FIG. 18, the optical switch 30 is arranged so as to be tilted in two axial directions with respect to the control light, the control light is made incident on the optical switch 30, and the signal light is transmitted to the optical switch 3.
The light may be incident perpendicularly to zero. In this case, since the control light pulse sequentially irradiates each area of the optical switch 30 and sequentially makes the light transmitting state, when the signal light pulse reaches the optical switch 30, the control light pulse is applied to the optical switch 30. The tilt of the optical switch 30 in the biaxial direction with respect to the control light may be determined so as to reach a region corresponding to the signal light pulse, and the control light may be synchronized with the signal light. Sequentially arrive at the optical switch 30, the spatial position portion of the signal light pulse corresponding to the signal light pulse passes through the region of the optical switch 30 corresponding to the signal light pulse, and is cut out as an output light pulse. Will be able to

Further, even if the optical switch is a reflection type, the serial signal light can be spatially converted into a two-dimensional parallel signal light similarly to the above-mentioned transmission type.

In this case as well, each output light pulse is placed on the optical path of the signal light or control light in FIG. 19 so that there is no spatial overlap between adjacent output light pulses.
The optical switch is disposed as shown in FIG. 15 or the independent reflective layer 36 as shown in FIG.
Are desirably two-dimensionally arranged in one direction and the other direction.

Further, when using an optical device that generates phase conjugate light using phase conjugate light, the serial signal light is spatially converted into two in the same manner as when an optical switch is used.
It can be converted to dimensional parallel signal light.

In this case, as in the case of converting into one-dimensional parallel signal light as shown in FIG. 7 or FIG. 11, by using a mirror, forward pump light and backward pump light can be formed. Further, by disposing a 波長 wavelength plate between the phase conjugate light generating device and the mirror, the polarization directions of the forward pump light and the backward pump light are made orthogonal to each other, and the phase conjugate light as output light is used as a signal light probe. The polarization can be orthogonal to the light.

[0166]

As described above, according to the optical distribution method of claim 1 or the optical distribution device of claim 19, 1Tbi
A serial signal light having a high bit rate of t / s or more can be directly and easily converted into a spatially one-dimensional multi-channel parallel signal light.

The light distribution method according to claim 2 or claim 20
According to this optical distribution device, a serial signal light having a high bit rate of 1 Tbit / s or more can be directly and easily converted into a spatially two-dimensional multi-channel parallel signal light.

Further, according to the light distribution method of claim 8 or the light distribution device of claim 26, the intensity of the output light can be increased, and the light distribution method of claim 10 or the light distribution method of claim 28 According to the light distribution device, the intensity of the output light can be further increased.

The optical switch according to claim 37 or 38 or the optical device according to claim 39 is suitable for use in the above-described light distribution method or light distribution apparatus.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a light distribution method and a light distribution device of the present invention.

FIG. 2 is a diagram provided for explanation of the method or apparatus of FIG. 1;

FIG. 3 is a diagram showing another embodiment of the light distribution method and the light distribution device of the present invention.

FIG. 4 is a diagram provided for explanation of the method or apparatus of FIG. 3;

FIG. 5 is a diagram showing still another embodiment of the light distribution method and the light distribution device of the present invention.

FIG. 6 is a diagram showing still another embodiment of the light distribution method and the light distribution device of the present invention.

FIG. 7 is a diagram showing still another embodiment of the light distribution method and the light distribution device of the present invention.

FIG. 8 is a diagram provided for explanation of the method or apparatus of FIG. 7;

FIG. 9 is a diagram illustrating an optical system that generates phase conjugate light.

FIG. 10 is a diagram illustrating an optical system that generates phase conjugate light of polarization orthogonal to probe light.

FIG. 11 is a diagram illustrating a light distribution method and a light distribution device used in an experiment when phase conjugate light is used.

FIG. 12 is a diagram showing one embodiment of a transmission type optical switch of the present invention.

FIG. 13 is a diagram illustrating a light distribution method and a light distribution device used in an experiment when a transmission type optical switch is used.

FIG. 14 is a diagram illustrating a light distribution method and a light distribution device used in an experiment when a transmission type optical switch is used.

FIG. 15 is a diagram showing one embodiment of the reflection type optical switch of the present invention.

FIG. 16 is a diagram illustrating a light distribution method and a light distribution device used in an experiment when a reflection type optical switch is used.

FIG. 17 is a diagram illustrating the principle of conversion into two-dimensional parallel signal light.

FIG. 18 is a diagram illustrating an embodiment of a light distribution method and a light distribution device when converting into two-dimensional parallel signal light.

FIG. 19 is a diagram illustrating a filter suitable for use in the method or apparatus of FIG. 18;

[Explanation of symbols]

1 ... Signal light, 1A-1F ... Signal light pulse, 1p-1u ...
Spatial position portion, 2 ... control light, 2a ... control light pulse, 3 ...
Output light, 3Ap to 3Fu, 3Au to 3Fp, 3a: output light pulse, Ep: probe light, Ef: forward pump light, E
b: backward pump light, Ec: phase conjugate light, 10: optical waveguide, 20: optical system, 30: optical switch, Wp to Wu: region, 32: functional thin film (base layer), 33: light shielding layer, 3
4: optical shutter section, 35: silicon substrate (substrate), 36
... reflection layer (effective switch unit), 40 ... optical element (optical processing element, photodetection element), 80 ... filter, 90 ... phase conjugate light generating device, 135 ... 1/4 wavelength plate, 136 ... mirror, 144 ... polarized light Beam splitter,

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasushi Sato 430 Nakai-cho Sakai-Kamigami-gun, Kanagawa Prefecture Green Tech Nakai Inside Fuji Xerox Co., Ltd.

Claims (39)

[Claims] An optical device having a predetermined width in one direction is disposed on an optical path of signal light composed of an optical pulse train,
The signal light and the control light synchronized with the signal light are respectively incident on the optical devices so that they intersect on the optical device and pass over the predetermined width, and are different from each other within the predetermined width of the optical device. An optical distribution method for generating output light pulses corresponding to different spatial position portions of different light pulses of the signal light from a region. 2. An optical device having a predetermined width spread in one direction and another direction intersecting the same, a tilt in two axial directions with respect to a signal light composed of an optical pulse train or a control light synchronized therewith. Having the signal light and the control light both intersect on the optical device;
In addition, the signal light is incident on the optical device so as to extend over a predetermined width in each of the one direction and the other direction, and the signal light is different from different regions within the predetermined widths in the one direction and the other direction of the optical device. A light distribution method for generating output light pulses corresponding to different spatial positions of light pulses. 3. The optical distribution method according to claim 1, wherein an optical switch whose on / off state is switched depending on whether control light having a predetermined intensity or more is irradiated is used as the optical device, and the output light pulse is used as the output light pulse. And an optical distribution method for cutting out different spatial position portions of different light pulses of the signal light. 4. The optical distribution method according to claim 3, wherein the control light is vertically incident on the optical switch, the different regions of the optical switch are simultaneously turned on, and the signal light is obliquely applied to the optical switch. Light distribution method to make light incident on 5. The optical distribution method according to claim 3, wherein the control light is obliquely incident on the optical switch, the different regions of the optical switch are sequentially turned on, and the signal light is transmitted to the optical switch. A light distribution method for vertically incident light. 6. The optical distribution method according to claim 3, wherein the optical switch is provided only at the moment when the control light is emitted.
A light distribution method in which the signal light is transmitted with a transmittance of a predetermined value or more as an ON state. 7. The optical distribution method according to claim 3, wherein the optical switch is provided only at the moment when the control light is emitted.
A light distribution method in which the signal light is reflected at a reflectance equal to or higher than a predetermined value as an ON state. 8. The optical distribution method according to claim 1, wherein the probe light as the signal light and the pump light as the control light are simultaneously irradiated as the optical device.
An optical distribution method using a light that generates a phase conjugate light of the probe light as the output light pulse. 9. The light distribution method according to claim 8, wherein the first pump light, which is the control light, is vertically incident on the optical device from one surface of the optical device, and the other surface of the optical device. Place a reflector on the
The pump light transmitted through the optical device from the one surface side is reflected by the reflecting mirror, and as a second pump light,
Simultaneously with the first pump light, the probe light, which is the signal light, is perpendicularly incident on the optical device from the other surface, and the probe light, which is the signal light, is obliquely applied to the optical device simultaneously with the first and second pump lights. Light distribution method to be incident. 10. The light distribution method according to claim 9, wherein a wavelength plate is disposed between said optical device and said reflecting mirror, and said first and second pump lights have polarization directions orthogonal to each other. Light distribution method. 11. The light distribution method according to claim 10, wherein an output light pulse generated from said optical device is extracted by a polarization beam splitter. 12. The light distribution method according to claim 8, wherein said optical device is a semiconductor fine particle dispersed glass or a metal fine particle dispersed glass. 13. The light distribution method according to claim 8, wherein said optical device is a semiconductor material or a semiconductor multiple quantum well. 14. The light distribution method according to claim 8, wherein the optical device is a polymer organic thin film, an organic crystal thin film, or an organic associated thin film. 15. The light distribution method according to claim 1, wherein each of the output light pulses has no spatial overlap with an adjacent output light pulse. 16. The optical distribution method according to claim 15, wherein each of the output light pulses is obtained as having no spatial overlap with an adjacent output light pulse.
An optical distribution method using a filter. 17. The light distribution method according to claim 1, wherein said output light pulses are processed by a spatial light modulator or another light processing element. 18. The light distribution method according to claim 1, wherein each of the output light pulses is detected by a light detection element. 19. A signal light optical system for expanding a wave front of a signal light composed of an optical pulse train in at least one axis direction perpendicular to the traveling direction, and at least one axis synchronized with the signal light and perpendicular to the traveling direction. A control light source that generates control light having a wavefront expanded in a direction, a signal light from the signal light optical system having a predetermined width in one direction, and control light from the control light generation source. Output corresponding to different spatial position portions of different light pulses of the signal light from the signal light optical system from different regions within the predetermined width by irradiating each other over the predetermined width. An optical device that generates an optical pulse. 20. A signal light optical system for expanding a wavefront of signal light composed of an optical pulse train in a plane direction perpendicular to the traveling direction, and a signal light optical system synchronized with the signal light and extending in a plane direction perpendicular to the traveling direction. A control light source for generating a control light having a widened wavefront; and a signal light from the signal light optical system or the control light generation, each of which has a predetermined width in one direction and another direction intersecting the same. With respect to the control light from the source, the control light from the signal light optical system and the control light from the control light source intersect with each other, and are arranged so as to have a tilt in two axial directions with respect to the control light from the source. By irradiating over a predetermined width in each of the one direction and the other direction, different spaces of different light pulses of the signal light from the signal light optical system from different regions within the respective predetermined widths in the one direction and the other direction. In the position part Optical distributor comprising an optical device that generates an output light pulses response, the. 21. The optical distribution device according to claim 19, wherein an optical switch whose on / off state is switched according to whether control light having a predetermined intensity or more is irradiated is used as the optical device, An optical distribution device in which different spatial position portions of different light pulses of signal light from the signal light optical system are cut out. 22. The optical distribution device according to claim 21, wherein control light from said control light generation source is vertically incident on said optical switch, said different areas of said optical switch are simultaneously turned on, and An optical distribution device in which signal light from an optical optical system is obliquely incident on the optical switch. 23. The optical distribution device according to claim 21, wherein the control light from the control light source is obliquely incident on the optical switch, and the different areas of the optical switch are sequentially arranged.
An optical distribution device which is turned on and in which signal light from the signal light optical system is vertically incident on the optical switch. 24. The optical distribution device according to claim 21, wherein the optical switch is turned on only at a moment when the control light from the control light source is irradiated. An optical distribution device for transmitting signal light with a transmittance of a predetermined value or more. 25. The optical distribution device according to claim 21, wherein the optical switch is turned on from the signal light optical system only at the moment when the control light from the control light source is irradiated. An optical distribution device which reflects the signal light of the above with a reflectance equal to or higher than a predetermined value. 26. The optical distribution device according to claim 19, wherein the optical device outputs the probe light pulse as the output light pulse when the probe light as the signal light and the pump light as the control light are simultaneously irradiated. An optical distribution device that generates phase conjugate light of light. 27. The optical distribution device according to claim 26, wherein the first pump light, which is the control light, is vertically incident on the optical device from one surface of the optical device, and the other surface of the optical device. A reflector is placed on the
Pump light transmitted through the optical device from the one surface side is reflected by the reflecting mirror, and is perpendicularly incident on the optical device from the other surface side simultaneously with the first pump light as a second pump light. An optical distributor in which the probe light, which is the signal light, is obliquely incident on the optical device simultaneously with the first and second pump lights. 28. The light distribution device according to claim 27, wherein a wave plate is arranged between said optical device and said reflecting mirror, and said first and second pump lights have polarization directions orthogonal to each other. Light distribution equipment. 29. The light distribution device according to claim 28, wherein an output light pulse generated from said optical device is extracted by a polarization beam splitter. 30. The light distribution device according to claim 26, wherein the optical device is a semiconductor fine particle dispersed glass or a metal fine particle dispersed glass. 31. The light distribution device according to claim 26, wherein the optical device is a semiconductor material or a semiconductor multiple quantum well. 32. The light distribution device according to claim 26, wherein the optical device is a polymer organic thin film, an organic crystal thin film, or an organic associated thin film. 33. The light distribution device according to claim 19, wherein each of the output light pulses has no spatial overlap with an adjacent output light pulse. 34. The optical distribution device according to claim 33, wherein each of the output light pulses is obtained as having no spatial overlap with an adjacent output light pulse.
An optical distribution device including a filter. 35. The light distribution device according to claim 19, further comprising a spatial light modulator or another light processing element for processing the respective output light pulses. 36. The light distribution device according to claim 19, further comprising a light detection element for detecting each of the output light pulses. 37. A light-shielding layer comprising a base layer made of a functional material whose absorption coefficient changes depending on whether or not control light is irradiated, and a light-shielding layer formed on the base layer. An optical switch that is not covered by and functions as a plurality of optical shutter units independent of each other. 38. A semiconductor device comprising: a substrate; and a reflective layer formed on the substrate, the reflectance of which varies depending on whether or not control light is irradiated. Optical switch that functions as 39. A base layer made of a functional material that generates a phase conjugate light of the probe light when the probe light and the pump light are simultaneously irradiated, and a light-shielding layer formed on the base layer. An optical device in which a portion of the base layer that is not covered with the light-shielding layer functions as a plurality of phase conjugate light generating units independent of each other.