JPH04181785A - Laser frequency sweep control circuit - Google Patents

Abstract

PURPOSE:To increase the frequency sweeping amount of a laser light and to improve the quality by providing a power amplifier for outputting a voltage across a capacitor, and an electro-optical element for sweeping the frequency of the incident light based on the voltage to output it. CONSTITUTION:Semiconductor element groups 8 are simultaneously conducted based on a control signal by a power amplifier 3A composed of a voltage power source 5 for supplying a high voltage, a series circuit having a reactor 6 and a capacitor 7 and connected to the positive terminal of the source 5 and the groups 8 connected in series and parallel with each other to be connected in parallel with the source 5 to output a voltage across the capacitor 7. An incident laser light La is swept in its frequency based on the voltage by an electro- optical element 2 and output. Thus, the amplifier 3A and the element 2 which sweeps the frequency of the incident light La based on the voltage and outputs it, are provided. Thus, the frequency sweeping amount of the light La can be largely increased, and the quality can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a laser frequency sweep control circuit that controls frequency sweep of laser light.

[Conventional technology] The configuration of a conventional example will be explained with reference to FIG.

FIG. 13 is a block diagram showing a conventional laser frequency sweep control circuit disclosed in, for example, US Pat. No. 4,636.287.

In Fig. 13, (1) is a laser source such as an argon laser, the laser beam output from the laser source (1), and (2) is the electricity used to sweep the frequency of the laser beam La. The optical element, Lb is a laser output light whose frequency has been swept, (3) is a power amplifier that applies an electric field to the electro-optical element (2), and (4) is an oscillator that provides a control signal to this power amplifier (3). It is.

Next, the operation of the conventional example described above will be explained.

Laser light La emitted by a laser source (1) is incident on an electro-optical element (2) that can sweep the frequency. At this time, the output Ux of the power amplifier (3) controlled by the oscillator (4) is given so that the electric field within the electro-optical element (2) changes in a time-dependent manner, and as a result, the output Ux of the power amplifier (3) is controlled by the oscillator (4). ) The refractive index of the laser beam passing through changes over time.

The amount of change Δn in the refractive index within the electro-optical element (2) is.

It is given by Δn ” k O' n 37"' 2 'E. Here, Ko is a constant, n is a refractive index, and E is an electric field. If a voltage that causes the electric field E to fluctuate over time is applied from the power amplifier (3), the frequency sweep amount Δf of the laser beam La becomes Δf=, d(Δn)/dlf=, dE/ dt l = K 3 ·d v x/ d t ·1. Here, K1, K2, and K3 are constants, and p is the length within the electro-optical element (2) through which the laser beam La passes. That is, by controlling the amount of change over time of the voltage υX applied from the power amplifier (3), the laser output light Lb in which the frequency of the laser light La is swept can be obtained.

[Problem to be solved by the invention] In the conventional laser frequency sweep control circuit as described above, 1
A high dυx/dt is required to significantly change the amount of frequency sweep, and the power amplifier (3) needs to control high voltage at high speed. There was a problem in that the frequency was small and it was impossible to increase the amount of frequency sweep.

Furthermore, when vacuum tubes that can handle high voltages are used, there are problems with reliability, lifespan, etc., and there is a problem in that quality is significantly degraded.

This invention was made in order to solve the above-mentioned problems, and aims to obtain a laser frequency sweep control circuit that can significantly increase the frequency sweep amount of laser light and improve the quality. .

[Means for Solving the Problems] A laser frequency sweep control circuit according to the first aspect of the present invention includes the following means.

[1] Consisting of a high-voltage power supply that supplies high voltage, a series circuit consisting of a reactor and a capacitor and connected to the positive terminal of the high-voltage power supply, and a group of series-parallel semiconductor elements connected in parallel to the high-voltage power supply, A power amplifier that turns on the semiconductor elements all at once based on a control signal and outputs a voltage across the capacitor.

[2] An electro-optical element that sweeps the frequency of the incident laser light based on the voltage and outputs the same.

Further, a laser frequency sweep control circuit according to a second aspect of the present invention includes the following means.

[1] A series circuit consisting of a high voltage power supply that supplies high voltage, a reactor and a capacitor and connected to the positive terminal of the high voltage power supply, and a group of series-parallel semiconductor elements connected in parallel to the high voltage power supply. A power amplifier that outputs a voltage across the reactor by making the semiconductor element group conductive all at once based on a control signal.

[2] An electro-optical element that sweeps the frequency of the incident laser light based on the voltage and outputs the same.

Further, a laser frequency sweep control circuit according to a third aspect of the present invention includes the following means.

[1] A high-voltage power supply supplying a high voltage, a series circuit comprising a reactor and a first capacitor and connected to the positive electrode of the high-voltage power supply, and a parallel circuit comprising a variable resistor and a second capacitor connected to the series circuit; and a power supply comprising a group of series-parallel semiconductor elements connected in parallel to the high-voltage power supply, and outputting the voltage across the second capacitor by making the semiconductor element group conductive all at once based on a control signal. amplifier.

[2] An electro-optical element that sweeps the frequency of the incident laser light based on the voltage and outputs the same.

[Operations] In the invention of the first claim, there is provided a high-voltage power supply supplying a high voltage, a series circuit comprising a reactor and a capacitor connected to the positive terminal of the high-voltage power supply, and a series-parallel circuit connected in parallel to the high-voltage power supply. A power amplifier made up of a group of semiconductor elements made conductive all at once based on a control signal, and outputs the voltage across the capacitor.

Further, the frequency of the incident laser light is swept by the electro-optical element based on the voltage and output.

In the invention of claim 2, there is provided a high-voltage power supply supplying a high voltage, a series circuit including a reactor and a capacitor connected to the positive terminal of the high-voltage power supply, and a series-parallel circuit connected in parallel to the high-voltage power supply. A power amplifier composed of a group of semiconductor elements causes the group of semiconductor elements to conduct simultaneously based on a control signal, and a voltage across the reactor is output.

Further, the frequency of the incident laser light is swept by the electro-optical element based on the voltage and output.

In the third aspect of the invention, there is provided a high-voltage power supply supplying a high voltage, a series circuit comprising a reactor and a first capacitor connected to the positive electrode of the high-voltage power supply, and a series circuit comprising a variable resistor and a second capacitor. A power amplifier configured of a parallel circuit connected to the high-voltage power supply and a group of series-parallel semiconductor devices connected in parallel to the high-voltage power supply causes the group of semiconductor devices to conduct simultaneously based on a control signal. The voltage across the second capacitor is output.

Further, the frequency of the incident laser light is swept by the electro-optical element based on the voltage and output.

[Examples] Five embodiments of the present invention will now be described in sequence.

First, the configuration of a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

The first section is a block diagram showing a first embodiment of the present invention, which is completely the same as the conventional circuit except for the power amplifier (3A).

FIG. 2 shows a power amplifier (3A) according to the first embodiment of the present invention.
FIG.

In FIG. 2, (5) is a high-voltage power supply, (6) is a beam axle, (7) is a capacitor, and (8) is a group of semiconductor elements in which, for example, FETs are connected in series and parallel.

Next, the operation of the first embodiment described above will be explained with reference to FIG.

3(a) to 3(d) are timing charts showing the operation of the power amplifier (3A) according to the first embodiment of the present invention.6 In FIG. 3, the horizontal axis represents time t, and the vertical axis represents time t. (a) is the control signal υ. , (b) shows the current io, (c) shows the output voltage Ux, and (d) shows the time change dE/dt of the electric field E.

The control signal U0 output from the oscillator (4) is supplied to the gate of each element of the semiconductor element group (8) connected in series and parallel. Terminals a and b at both ends of the capacitor (7) are treated as the output terminals of the power amplifier (3A), and the electro-optical element (
2) is applied.

A high voltage is charged to the capacitor (7) from the high voltage power supply (5) through the handle (6). At this time, the control signal υ. When the semiconductor element group (8) is brought into conduction simultaneously, the reactor (
6) and a capacitor (7), a current 10 with an oscillating frequency determined by the capacitor (7) flows in the closed circuit.

Therefore, as shown in FIG. 3(c), the capacitor (
7) The voltage υX at both ends is also the oscillating current i. vibrates at the same frequency. Here, U× is υx=Vkc o s (t
/ (LC) '') where Vk is the initial voltage value charged in the capacitor 7), L is the inductance value of the axle (6), and C is the capacitance value of the capacitor (7).

Since the electric field E applied to the electro-optical element (2) is proportional to the voltage Ux, the time change dE/dt of the electric field E shown in FIG. 3(d) is dE/ato=-vk/< L
C) 1"・s i n (t/ (LC) ""t. Therefore, dE/dt is a function of Vk, L, and C. In other words, dE/dt is the value of Vk, L, and C. A desired value can be obtained by arbitrarily setting .

In addition, in this first embodiment, since a series-parallel semiconductor element group (8) is used as an element for switching the initial voltage value Vk, high-voltage switching can be performed at high speed without affecting the circuit. It has come true, d E,,,' d
By increasing t, it is possible to increase the amount of frequency sweep.

As mentioned above, the first embodiment of the present invention has a high voltage power supply (
A reactor (6) and a capacitor (7) are connected in series with 5), and a semiconductor element group (8) is connected in parallel with the high voltage power supply (5).
Since it is equipped with a power amplifier (3A) connected to the laser beam, the frequency sweep amount of the laser beam can be increased, and since all the switching elements are semiconductors, the reliability is high and the service life is long.

A second embodiment of the invention will be described with reference to FIGS. 4 and 5.

FIG. 4 is a circuit diagram showing a power amplifier (3B) according to a second embodiment of the present invention, and FIG. 5 is a timing chart 1 to 1 showing the operation of the power amplifier (3B) in FIG. 4.

The configuration of the second embodiment of the present invention is almost the same as the first embodiment described above, and the difference is that, as shown in FIG. 4, a reactor (
6) is taken out from terminals a and b at both ends.

In FIG. 5, as in FIG. 3, the horizontal axis represents time t, and the vertical axes represent control signal υ0, (b) current 10, (c) output voltage υ×, ( d) shows the time change d E , -' d t of the electric field E.

The functions and effects of the second embodiment of the present invention are similar to those of the first embodiment described above.

A third embodiment of the invention will be described with reference to FIG.

The configuration of the third embodiment of the present invention is completely the same as that of the conventional circuit except for the power amplifier (3C).

FIG. 6 shows a power amplifier (3C) according to a third embodiment of the present invention.
is a circuit diagram showing a high voltage power supply (5) to a semiconductor element group (
8) is the same as that of the power amplifier (3A) of the first embodiment described above.

In FIG. 6, (9) is a variable resistor.

Next, the operation of the third embodiment described above will be explained with reference to FIGS. 7 and 8.

7(a) to 8(d) and FIG. 8 are timing charts showing the operation of the power amplifier (3C) of the third embodiment of the present invention.

In FIG. 7, the horizontal axis represents time pt, and the vertical axes are (a) control signal U0, (b) current 1o, (c) output voltage U×, and (d) time of electric field E. The change dE/dt is shown.

In FIG. 8, the horizontal axis represents time t, and the joint axis represents the time change dE/dt of the electric field E.

Control signal υ output from the oscillator (4). is supplied to the gate of each element of the semiconductor element group (8) connected in series and parallel. Terminals a and b at both ends of the capacitor (7) are treated as output terminals of the power amplifier (3C), and the electro-optical element (
2) is applied.

A high voltage is charged to the capacitor (7) from the high voltage power supply (5) through the handle (6). At this time, the control signal υ. When the semiconductor element group (8) is brought into conduction simultaneously, the reactor (
6), the current i at the vibration frequency determined by the capacitor (7) and the variable resistor (9). flows in a closed circuit.

Therefore, as shown in FIG. 7(c), the capacitor (
The voltage Ux across 7) also oscillates at the same frequency as the oscillating current 10. Here, Ux is Ux=Vk,'(I R2
Cz'4L)""-ε-"-5in(ωt+jan-'
(ω, /α)). Here, V k is the initial voltage value charged in the capacitor (7), and R is the variable resistor (9
) resistance value, C is the capacitance value of the capacitor (7), inductance value of the L beam axle (6), α-R/2L, ω=
(1,,・'LC) −(R/2 L)! ”2
, R2<(4L/C).

Since the electric field E applied to the electro-optical element (2) is proportional to the voltage Ux, the time change dE, /dt of the electric field E shown in FIG. 3(d) is dE,'dt. Eichi 2Vk, / (4LC-R2C2)"'・ε-"ts
inωt roar. Therefore, dE/dt is Vk, L, C1Rt7
) becomes a function. In other words, dE/dt is Vk, L, C, R
A desired value can be obtained by arbitrarily setting the value of .

In addition, as shown in FIG. 8, the resistance value R of the variable resistor (9)
By changing dE/dt, the value of dE/dt can be greatly controlled.

In addition, in this third embodiment, since a series-parallel semiconductor element group 8) is used as an element for switching the initial voltage value Vk, high-voltage and high-speed switching without affecting the circuit can be realized. , dE/dt can be increased, and the frequency sweep amount can be increased.

As mentioned above, the third embodiment of the present invention has a high voltage power supply (
5), a reactor (6), a capacitor (7), and a variable resistor (9) are connected in series with the power amplifier (3C), and a semiconductor element group (8) is connected in parallel with the high-voltage power supply (5). Therefore, the amount of frequency sweep of the laser beam can be increased, and since all the switching elements are semiconductors, the reliability is high and the service life is long.

A fourth embodiment of the invention will now be described with reference to FIG.

FIG. 9 is a circuit diagram showing a power amplifier (3D) according to a fourth embodiment of the present invention.

The configuration of the fourth embodiment of the present invention is almost the same as the third embodiment described above, and the difference is that, as shown in FIG. 9, a reactor (
6) is taken out from terminals a and b at both ends.

The functions and effects of the fourth embodiment of the present invention are similar to those of the third embodiment described above.

A fifth embodiment of the present invention will be described with reference to FIG. 10.

The configuration of the fifth embodiment of the present invention is completely the same as that of the conventional circuit except for the power amplifier (3E).

FIG. 10 shows a power amplifier (3E) according to a fifth embodiment of the present invention.
), which includes a high-voltage power supply (5) to a variable resistor (9).
) is the same as that of the power amplifier (3C) of the third embodiment described above.

In FIG. 10, (10) is a capacitor connected in parallel to the variable resistor (9).

Next, the operation of the fifth embodiment described above will be explained in FIGS. 11 and 1.
This will be explained with reference to Figure 2.

FIGS. 11(a) to 12(d) and FIG. 12 are timing charts showing the operation of the power amplifier (3E) of the fifth embodiment of the present invention.

In FIG. 11, the horizontal axis represents time t, and the vertical axis represents the control signal υ. , (b) is the current i. ,(c)
is the output voltage υ×, (d) is the time change of the electric field E dE/dt
It shows.

In FIG. 12, the horizontal axis represents time t, and the vertical axis represents electric field E.
It shows the time change dE/dt.

Control signal υ output from the oscillator (4). is supplied to the gate of each element of the semiconductor element group (8) connected in series and parallel. Terminals a and b at both ends of the capacitor (1o) are
It is treated as the output terminal of the power amplifier (3E) and applied to the electro-optical element (2).

A high voltage is charged to the capacitor (7) from the high voltage power supply (5) through the handle (6). At this time, when the semiconductor element group (8) is simultaneously made conductive by the control signal U0, the reactor (6), the capacitor (7) and the variable resistor (9 ) and the capacitor (10), a current j0 with an oscillation frequency determined by the capacitor (10) flows in the closed circuit.

Therefore, as shown in FIG. 11<c), the voltage U× across the capacitor (10) is also equal to the oscillating current i.

vibrates at the same frequency. Hereinafter, in order to simplify the explanation, the resistance value of the variable resistor (9) will be treated as infinite. Here, (/X is given by vx = (CI/C2) ・Vk (1-cosωt). where, C4 is the capacitance value of capacitor (7), C2 is the capacitance value of capacitor (10), Vk is the initial voltage value charged in capacitor (7), ω= +CI/L
(CI/C2+ 1) ) ””, L is the reactor (
6) is the inductance value.

Since the electric field E applied to the electro-optical element (2) is proportional to the voltage υX, the electric field E shown in FIG. 11(d)
The time change dE/'dt is d E , / d t 0
1: (IJ , (CI/'C2) ・Vks i nωt. Therefore, dE/dt is a function of Vk, L, C,, C2. In other words, dEz'dt is a function of Vk, L, C1,
A desired value can be obtained by arbitrarily setting the value of C2.

Note that, as shown in FIG. 12, the values of dE and /dt can be significantly controlled by changing the capacitance value C2 of the capacitor 10) connected in parallel to the variable resistor (9). However, C
, /C2>1.

In addition, in this fifth embodiment, a semiconductor element group (8) connected in series and parallel is used as an element for switching the initial voltage value ~·'k.
, it is possible to achieve high-voltage and high-speed switching without affecting the circuit, and it is possible to increase d E / d t and increase the amount of frequency sweep.

As mentioned above, the fifth embodiment of the present invention has a high voltage power supply (
5) and a reactor (6) and a capacitor in series with 7),
A power amplifier (3C) is connected to a parallel circuit of a variable resistor (9) and a capacitor (10), and a group of semiconductor elements (8) is connected in parallel to a high-voltage power supply (5). The frequency sweep amount can be large, and since all the switching elements are semiconductors, the reliability is high and the life span is long.

[Effects of the Invention] As explained above, the present invention, in the first claim, includes a high voltage power supply supplying a high voltage, a series circuit comprising a reactor and a capacitor and connected to the positive terminal of the high voltage power supply, and the high voltage power supply. a power amplifier consisting of a group of series-parallel semiconductor elements connected in parallel to each other, the power amplifier outputs the voltage across the capacitor by simultaneously conducting the semiconductor elements based on a control signal; and an incident laser. and an electro-optical element that sweeps the frequency of light based on the voltage and outputs the light. The reactor is composed of a series circuit connected in parallel to the high-voltage power supply, and a group of series-parallel semiconductor elements connected in parallel to the high-voltage power supply, and the semiconductor element group is made conductive all at once based on a control signal to output the voltage across the reactor. The third claim includes a power amplifier and an electro-optical element that sweeps the frequency of the incident laser light based on the voltage and outputs the frequency. a series circuit consisting of a variable resistor and a first capacitor connected to the positive terminal of the high voltage power supply; a parallel circuit consisting of a variable resistor and a second capacitor connected to the series circuit; and a series circuit connected in parallel to the high voltage power supply. A power amplifier is configured of a group of semiconductor elements arranged in parallel, and outputs a voltage across the second capacitor by making the semiconductor elements conductive all at once based on a control signal; Since the present invention includes an electro-optical element that sweeps and outputs the frequency based on the frequency, the frequency sweep amount of the laser beam can be significantly increased and the quality can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention, and FIG.
The figure is a circuit diagram showing a power amplifier according to a first embodiment of the present invention.
FIG. 3 is a timing chart diagram showing the operation of the power amplifier according to the first embodiment of the invention, FIG. 4 is a circuit diagram showing the power amplifier according to the second embodiment of the invention, and FIG.
Timing charts 1 to 1 showing the operation of the power amplifier of the embodiment
6 is a circuit diagram showing the power amplifier according to the third embodiment of the present invention, FIGS. 7 and 8 are timing charts showing the operation of the power amplifier according to the third embodiment of the present invention, and FIG. is a circuit diagram showing a power amplifier according to a fourth embodiment of the present invention;
FIG. 0 is a circuit diagram showing a power amplifier according to a fifth embodiment of the present invention, FIGS. 11 and 12 are timing charts showing the operation of the power amplifier according to a fifth embodiment of the present invention, and FIG. FIG. 2 is a block diagram showing a dozer frequency sweep control circuit. In the figure, (1) ... laser generation source, (2) - electro-optical element, (3A), (3B) ... power amplifier. (3C), (3D) ・Power amplifier, (3E) ・
Power amplifier, (4) Oscillator, (5) High voltage power supply, (6) Reactor, (7) Capacitor, (8) Semiconductor element group, (9) Variable resistor, (10)・ It is a capacitor. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (3)

[Claims] (1) Consisting of a high-voltage power supply that supplies high voltage, a series circuit consisting of a reactor and a capacitor connected to the positive terminal of the high-voltage power supply, and a group of series-parallel semiconductor elements connected in parallel to the high-voltage power supply, A power amplifier that simultaneously conducts the semiconductor elements based on a control signal and outputs the voltage across the capacitor, and an electro-optical element that sweeps the frequency of the incident laser light based on the voltage and outputs the same. A laser frequency sweep control circuit comprising: (2) consisting of a high-voltage power supply that supplies a high voltage, a series circuit comprising a reactor and a capacitor and connected to the positive terminal of the high-voltage power supply, and a group of series-parallel semiconductor elements connected in parallel to the high-voltage power supply; A power amplifier that makes the group of semiconductor elements conductive all at once based on a control signal and outputs a voltage across the reactor, and an electro-optical element that sweeps the frequency of the incident laser light based on the voltage and outputs it. A laser frequency sweep control circuit comprising: (3) High-voltage power supply that supplies high voltage, reactor and first
a series circuit comprising a capacitor connected to the positive terminal of the high voltage power supply, a parallel circuit comprising a variable resistor and a second capacitor connected to the series circuit, and a series-parallel circuit connected in parallel to the high voltage power supply. A power amplifier is configured of a group of semiconductor elements and outputs a voltage across the second capacitor by making the semiconductor elements conductive all at once based on a control signal, and a power amplifier that outputs the voltage across the second capacitor based on the voltage. A laser frequency sweep control circuit comprising an electro-optical element that sweeps and outputs a frequency.