JPH02230224A - Optical flip-flop - Google Patents

Abstract

PURPOSE:To make good use of the speediness that light has originally by controlling an optical signal with an optical signal without converting the optical signal into an electric signal. CONSTITUTION:The optical flip-flop has an optical gate OG1 having an optical bistable element BOD1 which receives hold light H and set light S and changes the states of transmitted light and reflected light according to the incidence state of the set light S and an optical gate OG2 having an optical bistable element BOD2 which changes the states of transmitted light and reflected light according to the incidence state of reset light R. Further, the hold light H which is reflected by the optical bistable element BOD1 is made incident on the optical bistable element BOD2 and the hold light H which is reflected by the optical bistable element BOD2 is made incident on the optical bistable element BOD1 by an optical feedback part. Consequently, the optical flip-flop which makes good use of the speediness of light is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to optical flip-flops driven and controlled by optical signals.

(Prior Art) In the prior art, there is no known device that performs an optical flip-flop operation without performing photoelectric conversion. A configuration shown in FIG. 2 can be considered as a configuration for performing an equivalent operation using conventional technology. That is, the optical set pulse S and the optical reset pulse R from the outside are detected by photodetectors DETI, DET2 such as photodiodes, and the respective output signals of these photodetectors DETI, DET2 are sent to the signal amplifiers AMI, AM2. The RS flip-flop EF is amplified by an electronic circuit.
Drive F. Further, a driver circuit Di, which causes the output signal to emit light from light emitting elements Ll, L2 such as semiconductor lasers,
This is applied to D2 to perform an optical flip-flop operation.

Alternatively, as shown in FIG. 3, it is also possible to optically feed back the output to form an optical flip-flop. In the figure, PDa and PDb are photodiodes, L
la, Llb, L2a, L2b are light emitting elements such as semiconductor lasers, Rla, Rib, R2a, R2b are adjustment resistors for operating as an optical flip-flop, HMI~
HM4 is a half mirror.

The anode of the photodiode PDa is the light emitting element Ll.
The anode of the light emitting element Lla is connected to one end of the resistor Rla, the cathode of the light emitting element Lla is connected to the DC power supply V-, and the other end of the resistor Rla is grounded. The cathode of the photodiode PDa is connected to the anode of the light emitting element L2a and also to the DC power supply V+ via the resistor R2a, and the cathode of the light emitting element L2a is grounded. The anode of the photodiode PDb is connected to the anode of the light emitting element Llb and one end side of the resistor Rib,
The cathode of b is connected to the DC power supply V-, and the resistor Rib
The other end is grounded.

The cathode of the photodiode PDb is connected to the anode of the light emitting element L2b, and also to the DC power supply V+ via the resistor R2b, and the cathode of the light emitting element L2b is grounded.

Further, the optical set pulse S is input to the photodiode PDb via the half mirror HM2, and the optical reset pulse R is input to the photodiode PDb via the half mirror HM4.
is incident on a. The light emitted from the light emitting element Lla is incident on the photodiode PDa, and the light emitted from the light emitting element Llb is incident on the photodiode PDb. The light emitted from the light emitting element L2a passes through the half mirror HMI to become a light output Q, and is also incident on the photodiode PDb via the half mirror HMI and the half mirror HM2. The light emitted from the light emitting element L2b is transmitted through the half mirror HM3 to become a light output Q', and is also incident on the photodiode PDa via the half mirror HM3 and the half mirror HM4.

When the optical set pulse S is incident on the optical flip-flop having the above-mentioned configuration, the reverse bias current of the photodiode PDb increases, so that the light emitting element L2b stops emitting light, and the optical output Q' becomes low level, and the photo Diode P
The intensity of light incident on Da decreases. As a result, the reverse bias current of the photodiode PDa decreases, so that the light emitting element L2a emits light and the optical output Q becomes high level. Since this configuration is symmetrical, the next time the optical reset pulse R is input, the optical output Q becomes low level and the optical output Q' becomes high level.

(Problem to be Solved by the Invention) However, in the conventional optical flip 7-flop, the operating time is determined by the upper limit of the operating speed of the electronic circuit, so the high speed that is the inherent characteristic of light cannot be fully utilized. First, it requires optical-to-electrical or electrical-to-optical conversion processing, and has drawbacks such as difficulty in processing a large number of signals at the same time.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an optical flip-flop that takes advantage of the high speed of light.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an optical flip-flop which performs a flip-flop operation by driving a pair of optical bistable elements complementarily by a hold light, a set light, and a reset light. In the first optical gate, the hold light and the set light are incident, and the first light gate has an optical bistable element that changes the states of transmitted light and reflected light depending on the incident state of the set light, and the hold light and the reset light are made incident thereto. , a second optical gate having an optical bistable element whose states of transmitted light and reflected light change depending on the incident state of the reset destination; and a hold light reflected by the optical bistable element of the first optical gate. The hold light that is incident on the optical bistable element of the second optical gate and reflected by the optical bistable element of the second optical gate is transmitted to the optical bistable element of the second optical gate.
An optical flip-flop is constructed, which includes a feedback section for transmitting light to the optical bistable element of the optical gate.

(Function) According to the present invention, for example, the hold light is always connected to the first and second lights.
When the set light is incident on the optical bistable element of the first optical gate, when the set light is incident on the optical bistable element of the first optical gate, the first
The incident light to the optical bistable element of the optical gate will be at a high level, and the light transmittance of the optical bistable element will increase. At this time, the hold light incident on the first optical gate passes through the optical bistable element of the first optical gate and is emitted without attenuation. As a result, the reflected light of the hold light by the optical bistable element of the first optical gate is attenuated, and the hold light and the optical bistable element of the first optical gate are transmitted to the second forward gate via the optical feedback section. The incident light to the optical bistable element of the second light gate becomes low level, the light transmittance of the optical bistable element decreases, and the incident light is reflected by the optical bistable element. The light is reflected and enters the first light gate via the light return section. As a result, the hold light that passes through the optical bistable element of the second front gate is attenuated.

Furthermore, even after the input of the set light to the first light gate is cut off, the hold light and the hold light reflected by the optical bistable element of the second light gate continue to enter the first light gate. , the incident light to the optical bistable element of the first optical gate maintains a high level, the incident light is transmitted through the optical bistable element of the first optical gate and exits, and this state is maintained.

After this, when the reset light is incident on the optical bistable element of the second optical gate, the incident light on the optical bistable element of the second optical gate becomes high level, and the light transmission of the optical bistable element rate increases. At this time, the hold light incident on the second optical gate passes through the optical bistable element of the second optical gate and is emitted without attenuation. This allows the second
The reflected light of the hold light by the optical bistable element of the first optical gate is attenuated, the incident light to the optical bistable element of the first optical gate is attenuated, and the light transmittance of the optical bistable element is reduced. The incident light is reflected by the optical bistable element of the first light gate, and
The light enters the second light gate via the light return section. As a result, the hold light that passes through the optical bistable element of the first optical gate is attenuated.

Furthermore, even after the input of the reset light to the second light gate is cut off, the hold light and the hold light reflected by the optical bistable element of the first light gate continue to enter the second light gate. , the incident light to the optical bistable element of the second optical gate maintains a high level, the incident light is transmitted through the optical bistable element of the second optical gate and output, and this state is maintained. This results in a flip 7 flop operation.

(Embodiment) FIG. 1 is a block diagram showing a first embodiment of the present invention. In the figure, F1 to F6 are single mode optical fibers (hereinafter simply referred to as optical fibers), FCMI to FCM6 are fiber collimators, and PR1 is an internal reflection mirror Mla, Mlb.
PR2 is a composite prism having reflection mirrors M2a and M2b inside, RL.
la, RL1b, RL2a, RL2b are rod lenses,
BODI and BOD2 are optical bistable elements consisting of nonlinear etalons, and OG1 and OG2 are optical gates.

Here, the rod lenses RL1a, RL1b, RL2a,
RL2b has a squared refractive index distribution in the radial direction, and the end face has a shape perpendicular to the optical axis, and a parallel point incident on one end face parallel to the optical axis is at the center of the other end face. The light is focused on (-axis center). Further, the incident light is a set light S, a reset light R, and a steady hold light H.

The hold light H guided through the optical fiber F1 is made into parallel light by the fiber collimator FCMI, and then passed through the composite prism P.
After passing through R1, rod lens RL of optical gate OG1
The light is input to the optical bistable element BODI via 1a. The hold light H guided through the optical fiber F2 is made into parallel light by the fiber collimator FCM2, and then passed through the composite prism PR.
After passing through I, the rod lens RL2 of the optical game OG2
The light is input to the optical bistable element BOD2 via a. Also,
The hold light H reflected by the optical bistable element BODI is reflected by the reflecting mirrors Mla and Mlb of the composite prism PRI, and enters the optical bistable element BOD2 via the rod lens RL2a of the optical gate OG2. Further, the hold light H reflected by the optical bistable element BOD2 is reflected by the reflecting mirrors Mla and Mlb of the composite prism PRI, and is incident on the optical bistable element BODI via the rod lens RL1a of the optical gate OG1.

The set light S guided through the optical fiber F3 is made into parallel light by the fiber collimator FCM3 and then passed through the composite prism PR.
After being reflected by the reflecting mirror M 2 a, the light is incident on the optical bistable element BODI via the rod lens RL1b of the optical gate OG1.

The reset light R guided through the optical fiber F4 is made into parallel light by the fiber collimator FCM4 and then passed through the composite prism P.
The light enters R2, is reflected by reflection mirror M2b, and then enters optical bistable element BOD2 via rod lens RL2b of optical gate OG2. Furthermore, the light transmitted by the optical bistable element BODI of the hold light H incident on the optical gate OGI via the fiber collimator FCMI is as follows:
The parallel light is made into parallel light by the rod lens RL1b, passes through the composite prism PR2, and is emitted as a light output Q to the optical fiber F5 via the fiber collimator FCM5. The transmitted light of the hold light H incident on the optical gate OG2 via the fiber collimator FCM2 through the optical bistable element BOD2 is converted into parallel light by the rod lens PR2 and transmitted through the compound prism PR2, and is then transmitted through the fiber collimator FCM6.
The light is outputted as a light output Q' to the optical fiber F6 via the light source.

In addition, each of the above-mentioned components includes the optical path of the set light S transmitted through the optical bistable element BODI, the optical path of the hold light H incident on the optical bistable element BODI, and the optical path of the hold light H reflected by the optical bistable element BODI. The optical path of the reset light R transmitted through the optical bistable element BOD2, the optical path of the hold light H incident on the optical bistable element BOD2, and the optical path of the hold light H reflected by the optical bistable element BOD2 are arranged so that the optical paths do not coincide with each other. and optical bistable element B so that they do not match.
An optical bistable element BO is installed so that the optical path of the set light S reflected by the ODI and the optical path corresponding to the optical output Q do not match.
Optical path of reset light R reflected by D2 and optical output Q'
are arranged so that the optical paths corresponding to the two do not coincide with each other.

Furthermore, a light shielding plate SP is provided between the reflecting mirror M 1 a and the reflecting mirror M1b of the composite prism PRI.

As a result, the optical bistable element BODI. Only the hold light reflected by each BOD2 is reflected by the reflecting mirror Ml.
a, Mlb. Also,
The composite prism PRI reflects the hold light H with an efficiency of 30% by the reflecting mirrors Mla and Mlb.

FIG. 4 is an enlarged view of the optical gate OG1 in the configuration example of FIG. 1. In the figure, M is a mirror and NL is a nonlinear medium layer. The nonlinear medium layer NL and the mirrors M on both sides constitute an etalon type optical bistable element BODI, and the rod lens R
An optical bistable element BOD1 is arranged between L1a, RL; lb, and the optical gate OGI is configured as a whole. Rod lenses RLla and RL1b are optical bistable elements BODI
An optical bistable element BODI is used in which parallel light incident thereon is focused on the optical bistable element BODI, and light emitted from the optical bistable element BODI becomes parallel light.

Next, a method for creating this optical gate OG1 will be explained.

First, AI2Ga was placed on a separately prepared GaAs substrate.
As, Q, 2μm, 75AOJ3 0.8
7 A! 1043G”0.67AS layer and 75A GaAs
Layers are stacked alternately in 100 layers. This GaAs and AI
0.33GaO. 67" are laminated alternately. The part is so-called M Q W (Multiple Quantum
Well) becomes the nonlinear medium layer NL in this configuration. Then, 8 layers of 2 97A TrO layers and 150A S L 0 layers were laminated alternately to form a mirror with a reflectance of 98% on one side.
Let it be M. The GaAs substrate on which the mirror M and the nonlinear medium layer NL are stacked on one side is placed with the surface with the mirror M facing down.
Adhere to rod lens RL2a.

Next, the excess GaAs substrate is etched and a protective layer of 0.2 μm A 1 o. Expose the aaG & ceyA S layer. On top of this, 8 TlO2 layers of 97A and 8 SiO2 layers of 150A are alternately laminated to form the mirror M on the opposite side. Furthermore, the optical gate OG1 is completed by adhering the rod lens RL2a to another prepared rod lens RL2b so that its optical axis coincides with that of the rod lens RL2a. The operating wavelength in this case is 0.87 μm. light gate OG2
The manufacturing method is also similar.

An optical flip-flop can be constructed by bonding each optical component as shown in FIG. 1 before and after the optical gates OG1 and OG2 produced in this way.

In the first embodiment, the mirror M is T i0 2/
It was constructed from a dielectric multilayer film mirror of SiO2, but
It is not limited to this, and in addition, ZnSe/N
It goes without saying that it can be constructed using a dielectric multilayer mirror such as a combination of aF.3AgF3, metals such as Cr, A, Q, Au, Ag, or composite films thereof. In addition, although the nonlinear medium layer NL is formed of a GaAslAIGaAs-based material, it is not limited to this.
a MQW of combinations such as InAs/AflInAs,
m-v group compound semiconductors such as GaAs, InP, InSb, 1nAs, II-Vl group compound semiconductors such as ZnSe, ZnS, CdS, CdTe, Te, CdHgTe, Cu
Semiconductors such as Ci), CdS Se etc. 1-x
Semiconductor-doped glass made by dispersing fine particles of a semiconductor with a diameter of about 100A in glass, boridiacetylene,
It goes without saying that it can be constructed using organic materials with large nonlinear constants such as 2-methylene and 4-nitroaniline.

Next, the principle of operation of the present invention will be explained based on FIGS. 5 to 8.

Figure 5 shows a nonlinear etalon with a maximum light transmittance of 80
The incident light intensity-transmitted light intensity characteristic of an optical bistable element having a ratio of .

In the figure, the horizontal axis represents the incident light intensity, and the vertical axis represents the transmitted light intensity. The difference (Δλ) between the resonant wavelength of the optical bistable element and the wavelength of the incident light is the predetermined wavelength Δλ. If it is larger, it shows bistability like curve A, and if it is smaller, it shows differential characteristics like curve B. Both the former and the latter are in a low transmission state when the incident light intensity is lower than a predetermined light intensity, and are in a high transmission state when it is higher than the predetermined light intensity.

Here, curve A is the difference between the resonance wavelength and the wavelength of the incident light (
Δλ) is the predetermined wavelength Δλ. Curve B shows the characteristics when the wavelength is 1.3 times as large as the wavelength of the incident light.
Δλ) is the predetermined wavelength Δλ.

The characteristics are shown when the ratio is 0.9 times.

Two optical bistable devices BOD having the characteristics described above are arranged symmetrically as shown in FIG. 6, and hold light H having the same light intensity is applied to each of both optical bistable devices BOD.
Let us consider a case where the hold light reflected by the optical bistable element BOD is fed back to the other optical bistable element BOD and is input to the other optical bistable element BOD. Here, the feedback efficiency is assumed to be 80%. The calculation results of the incident light intensity-transmitted light intensity characteristic of the optical bistable device BOD in this case are shown in FIGS. 7 and 8.

FIG. 7 shows that the difference (Δλ) between the resonant wavelength of the optical bistable device BOD and the wavelength of the incident light is the predetermined wavelength Δλ.

FIG. 8 shows the characteristics when the resonant wavelength of the optical bistable device BOD and the wavelength of the incident light (Δλ) is equal to the predetermined wavelength Δλ. The characteristics when the value is 0.9 times are shown.

In FIGS. 7 and 8, the horizontal axis represents the incident light intensity, and the vertical axis represents the transmitted light intensity.

In FIG. 7, when the intensity of light incident on the optical bistable element BOD is lower than the threshold value P1 or higher than the threshold value P2, the transmitted light intensity is uniquely determined. The intensity of light incident on the optical bistable element BOD is the threshold value P1 and the threshold value P2.
If the value is between 3 and 3 for one incident light intensity value,
There are three transmitted light intensity solutions x, y, and z, but the solution Y shown by the broken line is unstable and does not always take this value.

Further, in FIG. 7, ■ is the light intensity of the hold light H in FIG. 6, and T is the light intensity of the set light S or reset R in FIG. The light intensity I has a value between the threshold value P1 and the threshold value P2, and the sum of the light intensity ■ and the light intensity T has a value higher than the threshold value P2.

It is assumed that the two optical bistable devices BOD in FIG. 6 have the characteristics shown in FIG. When light H is incident, the optical bistable device BOD is in a high transmission state (one low reflection state) or a low transmission state (
(high reflex state). At this time, if both of the two optical bistable devices BOD are in a high transmission state, or if one optical bistable device BOD is in a high transmission state and the other optical bistable device BOD is in a low transmission state, or A case can be considered in which both are in a low transmission state. However, in a steady state, the law of conservation of energy for light input and output holds true, so one optical bistable element BOD is in a high transmission state,
The only possible state is when the other optical bistable element BOD is in a low transmission state.

Here, when a pulsed set light S having a light intensity T is incident on one of the optical bistable elements BOD which is in a low transmission state,
This optical bistable device BOD is in a highly transparent state. As a result, the hold light H incident on the one optical bistable element BOD is transmitted with almost no attenuation, and the optical output Q becomes a high level. Further, the one optical bistable element BOD
The reflected light of the hold light H attenuates, and the light returned to the other optical bistable element BOD, which was in a high transmission state, is attenuated, and the other optical bistable element BOD enters a low transmission state, and the hold light H is almost no longer transmitted, and the first output Q
' becomes low level. That is, by inputting the set light S into one of the optical bistable elements BOD, the states of the two optical bistable elements BOD are switched. Here, when a pulsed reset light R having a light intensity T is incident on the other optical bistable element BOD which is in a low transmission state,
The states of the two optical bistable elements BOD are switched again, and the optical output Q becomes low level, and the optical output Q' becomes high level. This performs a flip-flop operation.

Also, in the characteristic shown in FIG. 8, similarly to the characteristic shown in FIG. 7, there are three solutions for the transmitted light intensity for the incident light intensity having a value between two threshold values. It is clear that the same flip-flop operation as described above can be performed even if the optical bistable device BOD having the characteristics shown in FIG. 8 is used.

In this example, optical bistable devices BODI and BOD2 having the characteristics shown in FIG. 7 or 8 are used, and the light intensity I
A set light S and a reset light R having a light intensity T are used.

Next, the operation of this embodiment having the above-mentioned configuration will be explained based on the configuration diagram in FIG. 1 and the timing chart shown in FIG. 9. In FIG. 9, T is an optical bistable element BODI,
It shows the light intensity of the set light S1 and the reset light R incident on the BOD2.

Pthl indicates the intensity when the hold light H transmitted through the optical bistable element BODI is emitted as the optical output Q when the optical bistable element BODI is in a high transmission state, and PtII1
indicates the light intensity when the hold light H transmitted through the optical bistable element BODI is output as the optical output Q when the optical bistable element BODI is in a low transmission state. Also, Pth
2 indicates the light intensity when the hold light H transmitted through the optical bistable element BOD2 is output as the output Q' when the optical bistable element BOD2 is in a high transmission state, and Ptl2 is the optical intensity when the optical bistable element BOD2 is in a low transmission state. When the optical bistable element BO
It shows the light intensity when the hold light H transmitted through D2 is emitted as optical output Q'.

For example, assume that the initial state is that the optical bistable element BOD1 is in a low transmission state and the optical bistable element BOD2 is in a high transmission state.

At this time, the optical output Q has the optical intensity Pll, and the optical output Q'
has a light intensity Pth2.

Here, when the set light S is incident with light intensity T, the set light S is guided through the optical fiber F3, and is guided through the fiber collimator FC.
After being made into parallel light by M3, it is reflected by the reflecting mirror M2a of the composite prism PR2, and enters the optical bistable element BODI via the rod lens RL1b of the optical gate OGI. As a result, the intensity of light incident on the optical bistable element BOD1 increases, and the optical bistable element BODI changes from a low transmission state to a high transmission state after the switching time has elapsed. Accordingly, the reflected light of the hold light H that is fed back from the optical bistable element BODI to the optical bistable element BOD2 via the composite prism PRI is attenuated.

Therefore, the intensity of the light incident on the optical bistable element BOD2 decreases, the optical bistable element BOD2 changes to a low transmission state, and the hold light H incident on the optical bistable element BOD2 is reflected, and the composite prism PR1 The light is input to the optical bistable element BODI via the optical bistable element BODI. As a result, even after the input of the set light S to the optical bistable element BODI is cut off, this state is maintained, and the light intensity of the light output Q becomes a high level light intensity Pthl.
The light intensity of the light output Q' becomes a low level light intensity Ptl2. In this state, when the reset light R is incident with light intensity T, the reset light R is guided through the optical fiber F4, is made into parallel light by the fiber collimator FCM4, and is then reflected by the reflection mirror M2b of the composite prism PR2,
The light enters the optical bistable element BOD2 via the rod lens RL2b of the light gate OG2. As a result, the intensity of light incident on the optical bistable element BOD2 increases, and the optical bistable element BO
D2 changes from a low transmission state to a high transmission state after the switching time has elapsed. Along with this, the optical bistable element BOD2
The reflected light of the hold light H that is fed back from the optical bistable element BODI via the composite prism PRI is attenuated. Therefore, the intensity of light incident on the optical bistable element BODI decreases.

As a result, the optical bistable element BODI changes to a low transmission state, and the hold light H incident on the optical bistable element BOD1 is reflected by the optical bistable element BODI, and then passes through the optical bistable element PRI. B O D 2 1: Injected. After this, even after the input of the reset light R to the optical bistable element BOD2 is cut off, this state is maintained, the light intensity of the light output Q becomes a low level light intensity pH1, and the light intensity of the light output Q' becomes The light intensity becomes high level Pth2. The above-mentioned relationship between the number of people and the number of people is the same as that of an RS flip-flop in an electric circuit.

Further, in this embodiment, the separation of each light component is performed by shifting the axis of the optical system. This axis-shifting optical system is
Rod lenses RL1a, RL2 with squared refractive index distribution
a, RL2b, parallel to the axis
1a, RL1b, RL2a, and RL2b are configured so that all the light incident on the end face on one end side is focused on the center (-axis) of the end face on the other end side. Therefore, it is possible to construct an optical system with low loss without using a polarizing beam splitter, a quarter-wave plate, etc., and it is also possible to increase the feedback efficiency of the hold light H using the composite prism PRI. can. Furthermore, the degree of freedom in setting the optical system increases, that is, it is possible to easily adjust the position and installation of the fiber collimator, so the resonant wavelength of the optical bistable element can be finely adjusted at the incident position of the light. This makes it possible to control the light input/output characteristics of the optical bistable element, making it possible to easily perform flip-flop operation.

FIG. 10 is a configuration diagram showing a second embodiment of the present invention.

The difference between this second embodiment and the first embodiment is that semiconductor lasers LAI and LA are used as light sources for the hold light H at the respective positions of the fiber collimators FCMI and FCM2.
2 and rod lenses RL3 and RL4 are arranged, and the other configurations are the same as in the first embodiment. As a result, the hold light H emitted from the semiconductor laser LAI passes through the compound prism PR1 via the rod lens RL3.
After passing through the composite prism PRI, the light enters the optical bistable element BODI via the rod lens RL1a. Further, the hold light H emitted from the semiconductor laser LA2 passes through the compound prism P through the rod lens RL4.
The light enters the optical bistable element BOD2 via the rod lens RL2a after passing through the composite prism PRI.

The functions and effects of the second embodiment are similar to those of the first embodiment.

(Effects of the Invention) As explained above, according to the present invention, since an optical signal is controlled by an optical signal without converting the optical signal into an electrical signal, the high speed characteristic of light can be fully utilized. becomes possible.

Moreover, by integrating the optical parts and making it modular, there are advantages such as ease of handling and easy integration into other devices.

Further, by applying the optical flip-flop of the present invention, it is expected that electronic circuits such as counters and converters can be constructed from optical circuits.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of the present invention, FIG. 2 is a diagram showing a first conventional example, FIG. 3 is a diagram showing a second conventional example, and FIG. 4 is a diagram similar to that shown in FIG. Figure 5 is a diagram of the incident light intensity vs. transmitted light intensity characteristic of the optical bistable element, Figure 6 is an explanatory diagram of the operating principle, and Figure 7 is the incident light intensity vs. transmitted light characteristic of the optical bistable element. An intensity characteristic diagram, FIG. 8 shows an incident light intensity vs. transmitted light intensity characteristic diagram of an optical bistable element, FIG. 9 shows a timing chart in the first embodiment, and FIG. 10 shows a second embodiment of the present invention. FIG. F1 to F6...Single mode optical fiber, FCM1
~FCM6...Fiber collimator, OG1, OG
2-... Optical cell, BODI, BOD2... Optical bistable element, RL1b, RL2a, RL2b, RL3, RL
4...Rod lens, PRI, PR2...Composite prism, LAI, LA2...Semiconductor laser. Partially enlarged view of Figure 1 Figure 4 Incident light intensity Characteristic diagram of incident light intensity vs. transmitted light intensity of optical bistable element Figure 4 Figure 4 Funeral diagram Figure 4

Claims (1)

[Claims] In an optical flip-flop that performs a flip-flop operation by complementary driving a pair of optical bistable elements with a hold light, a set light, and a reset light, the hold light and the set light are incident, and the set light a first optical gate having an optical bistable element that changes the state of transmitted light and reflected light depending on the incident state of the light; a second optical gate having an optical bistable element in which the value of the optical bistable element changes; and a hold light reflected by the optical bistable element of the first optical gate is made incident on the optical bistable element of the second optical gate, and , an optical return section that causes the hold light reflected by the optical bistable element of the second optical gate to enter the optical bistable element of the first optical gate.