JPH02101788A - Excitation control equipment for laser amplifying equipment - Google Patents

Abstract

PURPOSE:To correct the fluctuation value of the ionization time of a thyratron for discharge excitation circuit, and restrain the fall fluctuation of laser output by a method wherein a processor for outputting a control signal to each variable delay circuit is provided, the processor instructs delay time, and further instructs a corrected delay time to a sequential variable delay circuit, when the time difference fluctuation between a detection signal and a repetition pulse signal is detected. CONSTITUTION:The fluctuation period of ionization time is much longer than that of the repetition frequency of excitation pulses of a laser amplifier 1a and the like, e.g., 5KHz, which is determined by a clock signal generator 7. On the contrary, at each clock signal of the clock signal generator, a processor 8 monitors the generation time of excitation pulse applied to the laser amplifier 1a, based on the detection signal from, e.g., a discharge light detector 5a. In the most rapid case, the processor corrects and sets the delay time of a variable delay circuit 6a before the next clock signal. As a result, the delay time setting of the variable delay circuit 6a and the like is capable of tracking correction of ionization time fluctuation of a thyratron 3a and the like. Thereby, the fluctuation of generation time of excitation pulse can be prevented, and the coincidence with the input timing of the pulse laser light from the pre-stage is always enabled, so that the laser light output can be kept constant.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention applies to an excitation control device for a laser amplifier device in which a plurality of discharge excitation pulse radars are connected in cascade.

(Prior art) For example, laser processing, photoreaction processing, I'Jt? As a method to increase the output of lasers used for excitation ionization of isotope atoms, etc., a first-stage laser device that functions as a laser oscillator is followed by a multi-stage series connection of laser devices that operate in response to the laser output of the previous stage. A laser amplifier device is used.

For example, metal gas lasers are used in this type of laser amplifier device, and excitation by pulsed discharge is often used to obtain output.

In this case, the discharge of the laser device in the subsequent stage must be performed in synchronization with the arrival time of the laser beam, which is delayed by the propagation time of the laser beam between the preceding stages from the discharge time of the laser device in the previous stage. A delay circuit is used in the signal circuit for discharge excitation.

(Problems to be Solved by the Invention) In the laser amplifier device as described above, a CYRAD [1] is often used as a switch for the discharge excitation pulse power supply circuit of each laser device constituting the laser amplifier device. However, with this cyratron, the time from when the trigger signal for starting spinning is given to the grid until the completion of discharge, that is, the ionization time, is about 20 to 100 nsec (for example, hydrogen thyratron), but this ionization The time will vary depending on external conditions such as the cathode heater voltage of the Cype 1-ron, ambient temperature, or the reservoir voltage of the circuit in which the 1-Nyratron is used. Therefore, the pulse width of the laser light handled by the laser amplifier device is, for example, about 30nsee, but due to fluctuations in the ionization time of the thyratron, the laser light arriving from the previous stage and the discharge time of the subsequent laser device do not match, which causes A problem has arisen in that the laser output to the laser amplifier device is reduced and the effectiveness of the laser amplifier device is diminished.

An object of the present invention is to correct the fluctuation value of the ionization time of the silad 0n for the 11i electric excitation circuit, and to suppress the decrease fluctuation of the sea 1f output.
! The objective is to provide a l device.

[Structure of the invention]

(Means for Solving the Problems) The present invention comprises optically cascade-connected laser oscillators and Rade amplifiers, inter-plane -f oscillators, and high-voltage pulse power supplies for laser excitation provided individually in the laser amplifiers. , a variable delay circuit which is provided in front of each of the trigger circuits of these high-voltage pulse power supplies and whose delay t+ is controllable, an oscillator that repeatedly supplies a pulse signal to each of these variable delay circuits, and a discharge of each of the laser amplifiers. comprising discharge light detection means for detecting each light, and a processor inputting each detection signal of these discharge light detection means and the repetitive pulse signal of the oscillator and outputting a control signal to each of the variable delay circuits, The processor instructs each of the variable delay circuits to set their delay times, and when a time difference variation between the detection signal of the excitation current detection means and the repetitive pulse signal of the oscillator is detected, the processor generates a correction delay that corrects the variation value. The present invention is characterized in that it has a processing means for sequentially instructing the corresponding variable delay circuit to change the time.

(Function) The variable delay circuit of the Rede amplifier has a delay time of the variable delay circuit of the laser oscillator. If the processor instructs in advance a delay time that is long enough to compensate for the difference in the delay time between receiving the trigger signal and generating the actuating current, the laser amplifier will be excited in accordance with the arrival time of the laser beam from the laser oscillator. , the output efficiency of the laser amplifier is best maintained.

Here, if the high voltage pulse power supply of the laser amplifier is
1. Even if there is a slight fluctuation in the delay time from reception of the RIGA signal to generation of excitation current, the processor immediately commands the variable delay circuit of the laser amplifier to set a corrected delay time that offsets this fluctuation, and adjusts the delay time accordingly. Since the excitation I
I height F [The pulse application time follows the laser beam arrival time, and it is possible to avoid a decrease in the output of the laser amplifier. Note that when the laser amplifier is continued in multiple stages, and also for the laser oscillator located at the first stage, the same effect as described above occurs for each of them.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In the figure, a laser amplifier 1a1 that receives the laser light output of the laser oscillator 1 at a certain distance (for example, 3 TrL) from a pulse-excited laser oscillator 1 constituted by a metal vapor laser, and a further certain distance away. A laser amplifier 1b is installed which receives the laser light output from the laser amplifier 1a and operates, respectively, so that the light output of the laser amplifier 1b is shared for a required purpose. Note that both the laser amplifier 1a and the laser amplifier 1b are metal vapor lasers like the laser ifi device 1.

A high-voltage pulse power source 2 for excitation is connected to the laser oscillator 1, and its main part is constituted by a thyratron 3 and a trigger circuit 4 connected to a grid of the thyratron 3.

Further, the laser oscillator 1 includes a -C discharge light detector 5 as a discharge light detection means for detecting discharge light generated when an excitation current flows. A high voltage pulsed voltage +1Ei2a and a high voltage pulsed voltage 1112b are connected to the laser amplifier 1a and the laser amplifier 1b, respectively. Since the configuration of these essential parts is equivalent to that of the high voltage pulse power source 2, the corresponding component numbers in the high voltage pulse power source 2 will be denoted by a or b, and individual explanations will be omitted.

A clock signal generator 7 is provided as a common trigger signal generation source for the trigger circuits 4.4a and 4b.

This repetition frequency is selected to be, for example, about 5K+-IZ. The output signal of the clock signal generator 7 is outputted from the variable delay circuits 6.6a and 6b to the circuit 4.
．． 4a and 4b. The delay times of the variable delay circuits 6 and the like can be individually set by external signals.

A processor 8 is also provided as a delay time setting value for the variable delay circuit 6, etc., and the processor 8 receives the clock signal of the clock signal generator 7 and the discharge light detector 5.5.
The detection signals a and 5b are input to the variable delay circuits 6.6a and eb, and the circuits are connected to output delay time control signals, respectively. The processor 8 stores the delay time initially set for each of the variable delay circuits 6.6a and 6b (set so that the maximum value of the laser output is obtained at the start of operation), and based on this delay time. The variable delay circuit 6S is provided with processing means for commanding the delay time setting value to the variable delay circuit 6S. After the power amplifier device starts operating, if the elapsed time from the clock signal to, for example, the detection signal of the discharge light detector 5 changes from the value at the start of operation, the difference is extracted and the delay time is calculated. The command value can be corrected and sent to the variable delay circuit 6. Note that the variable delay circuit 5a.

Similar processing can be performed for 6b as well.

Next, the action will be explained.

When the clock signal generation "jS7 is started, the clock signal passes through the variable delay circuit 6 and is delayed, and then becomes a trigger pulse by the circuit 4, and the thyratron 3
applied to the grid. After the ionization time has elapsed, the thyratron 3 discharges and generates a high voltage pulse, and the laser Q1ti
51 is repeatedly pulsed. The pulsed Raded light output of the Raded oscillator 1 thus generated is repeatedly applied to the laser amplifier 1a. The pulsed laser light that reaches the laser amplifier 51a is delayed from its generation time in the laser oscillator 1 by the propagation time of the distance between the laser oscillator 1 and the laser amplifier 1a. The C11 amplifier 1a is pulse excited to coincide with the arrival time of this delayed pulsed laser beam. 1. Clock signal generation: The clock signal of the device 7 is delayed by the variable delay circuit 6a and applied to the high voltage pulse voltage vA2a. The delay time set in the variable delay circuit 6a is roughly set in the variable delay circuit 6 (
The value is the sum of the delay time and the propagation time of the pulsed -If light described above. More details will be explained later. The laser amplifier 1a is excited by a high voltage pulse generated by the high voltage pulse power supply 2a through the same process as that for the laser oscillator 1 described above, and the generated laser light output is repeatedly applied to the laser amplifier 1b.

Note that the operational relationship of each of the C4 amplification widths 1b with respect to the laser amplifier 1a is the same as that with respect to the laser oscillator 1 of the laser amplification mla, so a description thereof will be omitted.

The delay time set in the variable delay circuit 6a has been briefly described above, and will now be described in detail.

When the ionization times of the thyratron 3 and the ionization times of the thyratron 3a are equal, the delay time set in the variable delay circuit 6a is equal to the delay time set in the variable delay circuit 6 as described above. The value is the sum of the propagation time between the laser oscillator 1 and the laser amplifier 1a. However, there are generally individual differences in the ionization times of the thyratron 3 and the reilatron 3a. Therefore, for example, if the ionization time of the thyratron 3a is longer than that of the thyratron 3, the delay time of the variable delay circuit 6a is set shorter by the difference.

Including the correction valve for individual differences in the ionization time of the thyratron 3, etc., the initial II setting of the extension time of the variable delay circuit 6, etc. is performed, for example, at the start of operation of the laser amplifier device, in other words, outside the laser amplification evaporation device. The processor 8 can be operated by an external means (not shown) and the delay times of the variable delay circuit 6a and below can be adjusted so that the maximum output of the laser amplifier 1b can be obtained while keeping the target f1 constant.

- Once each Sheet 11 amplifier 18 etc. is excited in accordance with the input of pulsed laser light from the previous stage and the laser amplifier device starts operating, the outside of the thyratron 3aM is The ionization time of Reira I/Ron 3a, etc. changes due to changes in the voltage applied to the cathode heater, ambient temperature, reservoir voltage, etc. 6, and the back of the variable delay circuit 68 etc. The delay times of the corresponding items are reset to compensate for this change. As a result, the excitation of the laser amplifier 1a etc. always coincides with the input timing of the pulsed laser light from the curved structure and does not deviate significantly, so the laser light output of the laser amplifier 1b can be maintained at the maximum value at the start of operation. Can be done.

That is, the above-mentioned variation period of the ionization time is much better than the repetition frequency of the excitation pulse of the laser amplifier 1a etc. determined by the clock signal generator 7, for example, the period of 5Kl-1z. On the other hand, for each clock signal of the clock signal generator 7, the processor 8 monitors the generation time of the excitation pulse applied to the laser amplifier 1a based on the detection signal from the discharge light detector 5a, for example, and In the fastest case, the variable delay circuit 6
The delay time of a can be reset. Therefore, the delay time settings of the variable delay circuit 68 and the like can track and correct ionization time fluctuations of the complete thyratron 38 and the like.

Note that variations in the ionization time of the thyratron 3 of the laser oscillator 1 do not affect the laser light output of the laser oscillation 4 itself, but if this varies, the pulsed laser from the preceding stage of the subsequent laser, amplifier 18, etc. This will induce variations in the light input timing and the excitation pulse.
The variable delay circuit 6 acts in the same manner as the variable delay circuit 6a and the like described above to prevent this.

〔Effect of the invention〕

According to the present invention, fluctuations in the generation time of the excitation pulse of each radar device constituting the laser amplifier device are prevented, and the timing can always be made to coincide with the input timing of the pulsed laser light from the previous stage, so that the laser beam of the laser amplifier device Output can be kept constant.

[Brief explanation of the drawing]

Please refer to the figure, which is a block connection diagram showing an embodiment of the present invention. 1... Laser generator, ia, ib... Ray amplifier, 2.2a, 2b... High voltage pulse power supply, 4... Trigger circuit, 5, 5a, 5b... Discharge light detection vessel, 6.6
a, 6b... variable delay circuit, 7... clock signal generator, 8... processor.

Claims (1)

[Claims] A laser oscillator and a laser amplifier optically connected in cascade, a high-voltage pulse power source for laser excitation provided individually for the laser oscillator and the laser amplifier, and a trigger circuit for each of these high-voltage pulse power sources, each of which is provided in advance and delayed. a time-controllable variable delay circuit, an oscillator that repeatedly supplies a pulse signal to each of these variable delay circuits, a discharge light detection means for detecting the discharge light of each of the laser amplifiers, and each detection of these discharge light detection means. a processor that inputs a signal and a repetitive pulse signal of the oscillator and outputs a control signal to each of the variable delay circuits, the processor instructs each of the variable delay circuits to delay their delay times, and detects the excitation current. The processing means is provided with a processing means for changing a time difference variation between the detection signal of the means and the repetitive pulse signal of the oscillator to a corrected delay time by correcting the variation value and sequentially instructing the corresponding variable delay circuit. An excitation control device for a laser amplifier device, characterized in that: