SU842749A1 - Radiation power stabilizing device - Google Patents

Description

(54) DEVICE FOR STABILIZATION OF RADIATION POWER

one

The invention relates to devices for controlling the radiation of an optical quantum generator (JAG) and can be used, in particular, in photometry as a pulsed source of optical radiation of stable amplitude and frequency.

A device for controlling the intensity of optical radiation is known, containing in series an optical controllable optical filter and a radiation flux divider arranged on the optical axis, at one of the outputs of which a spatial integrator and a radiation receiver are connected through a comparison unit to the input of the controlled optical filter, as well as on the second output of the radiation flux divider, a nonlinear radiation converter, successively located on the same optical axis, secondly An independent integrator and a second radiation receiver connected to the second input of the comparison unit 1.

The disadvantage of such a device is low speed.

The closest in technical essence to the present invention is a device for stabilizing power.

radiation, containing a successive working body, the first modulator, the first beam splitting element, the delay element and the second modulator, the control input of which is connected to the output of the control block, the output window of the first modulator connected via the first beam splitting element

0 by the input of the first photodetector, the output of which is connected to the input of the frequency control unit, the output connected to the control input of the first modulator 2.

five

A disadvantage of this device is the low accuracy of the device, since it does not compensate for fluctuations in the power of optical radiation pulses without distorting them.

0 forms. The power fluctuations of the optical radiation are smoothed by the second modulator, the optical density of which varies in accordance with the signal from the output of the control circuit,

5 to the input of which a signal is output from the output of the first photodetector containing information on fluctuations in the power of the optical signal. It is easy to see that if the optical signal is them

0 is pulsed, the signal at the output of the control circuit will also be pulsed, such that the second modulator controlled by it will smooth out the fluctuations of the pulses of the output signal, i.e. will change its optical density in accordance with the pulse shape, and the maximum density value will correspond to the maximum value of the radiation power. In addition, since the first photodetector, control circuit, and second modulator have well-defined frequency characteristics, this device does not fully compensate for power fluctuations (for example, the feedback circuit does not work out pulses shorter than the response time of the first photodetector, as a result of which , passes from the input to the output of the device without smoothing), and only compensates for fluctuations in a certain frequency range. For pulse signals, this gives distortion of the waveform. The purpose of the invention is to improve the accuracy of the device for stabilizing the radiation power. This goal is achieved in that the device for stabilizing the radiation power contains a pulse amplitude selection and storage unit, a second beam-splitting element and a second photodetector connected in series, an integrator and a reference signal regulating unit, the second comparator input through the selection and storage unit of the amplitude pulses associated with the output of the first photodetector, and the input window of the second photoreceiver through the second beam-splitting element is connected with the output window of the second modulator. The drawing shows the functional scheme of the device. The device for stabilizing the radiation power comprises a successively located working body 1, the first modulator 2, the first beam-splitting element 3, the delay element 4 and the second modulator 5, whose control input is connected to the output of the comparator 6, the output window of the first modulator 2 through the first Secondary beam splitter element 3 is connected to the input of the first photodetector 7, the output of which is connected to the input of frequency control unit 8, the output connected to the control input of the first modulator 2, and also the amplitude selection and storage unit 9 pulses of pulses, a second beam-splitting element 10, and a photodetector 11 connected in series, an integrator 12 a reference signal adjustment unit 13. The device works as follows. The frequency adjusting unit 8 controls the first modulator 2 in such a manner that the laser operates in synchronization mode. At the same time, at the output of the laser, a sequence of optical pulses of a fixed tracking frequency takes place. The feedback through the first beam-splitting element 3 and the first photodetector 7 and the frequency adjusting unit 8 are used to phase out the pulse sequence and to adjust in frequency. The main part of the radiation of the JAG is branched off by the first beam-splitting element 8 and through the series-connected delay element and the second modulator 5 enters the second beam-splitting element 10, which forwards the main part of the radiation to the output of the device, and delivers a small part to the second photodetector 11. In the first and second photodetectors 7 to 11, the optical pulse sequence is converted into a sequence of electrical pulses. The electrical signal from the first photodetector 7 is supplied, as already noted, to frequency adjustment unit 8 as a feedback signal. In parallel, this signal arrives at block 9 for the selection and storage of the amplitude, of pulses, which stores the value of the amplitude for the time of signal processing. The signal from the output of block 9 for selecting and storing the amplitude of the pulses is fed to comparator b, to another input of which a reference signal is received from the output of block 13 for controlling the reference signal. In comparator 6, a second modulator control signal 5 is generated. The control signal corresponds to the difference between the values of the current amplitude of the controlled signal and the amplitude of the reference signal and changes the optical density of the specified second modulator 5 in such a way as to stabilize the amplitude of the output signal . The delay time of the delay element 4 is equal to the response time of the electro-optical circuit: the first beam splitting element 3 is the first photodetector 7, the pulse amplitude block 9 and the amplitude of pulses — a comparator 6 is the second modulator 5. Thus, at that time, as the fth pulse of the sequence the optical pulses delivered by the laser passes the delay element 4; information about its amplitude is compared with the voltage reference value and a signal is generated for correcting the amplitude of this particular pulse and when the specified pulse passes through the second modulator 5, with its help the pulse amplitude is corrected. The signal from the output of the in-mountain pho-i of the receiver 11 enters through the intensity of the G – K – Gy-12, the constant integration of the K (.- I of the

significantly longer than the pulse period, as a result of which it converts the pulse sequence into a constant level signal to the input of the reference signal control unit 13. This signal is averaged over several values of the amplitude of the pulses and serves to eliminate the drift of the entire device over large periods of time.

Claims (2)

1. Author's certificate of the USSR 547737, cl. G 05 D 25/00, 1977. 2. USSR author's certificate 0 No. 688899, cl. G 05 O 25/00, 05/30/78 (prototype).