CN112180394B - Multi-longitudinal-mode high-spectral-resolution laser radar interferometer frequency locking system - Google Patents
Multi-longitudinal-mode high-spectral-resolution laser radar interferometer frequency locking system Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/88—Lidar systems specially adapted for specific applications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/88—Lidar systems specially adapted for specific applications
- G01S17/89—Lidar systems specially adapted for specific applications for mapping or imaging
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/4802—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/483—Details of pulse systems
- G01S7/484—Transmitters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/483—Details of pulse systems
- G01S7/486—Receivers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/483—Details of pulse systems
- G01S7/486—Receivers
- G01S7/4861—Circuits for detection, sampling, integration or read-out
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The invention discloses a multi-longitudinal mode high spectral resolution laser radar interferometer frequency locking system, which comprises a multi-longitudinal mode laser, a half wave plate, a polarization beam splitter prism, an acousto-optic modulation module, a spectrum frequency discrimination interferometer, a converging lens, a photoelectric detector, a peak value holding circuit and a proportion-integration-differential servo control module; the multi-longitudinal mode pulse laser output by the multi-longitudinal mode laser is subjected to beam splitting to obtain a low-power beam after passing through a half-wave plate and a polarization beam splitting prism; the low-power light speed is shifted in frequency by the acousto-optic modulation module and then enters the spectrum frequency discrimination interferometer, and the emergent light is received by the photoelectric detector after passing through the converging lens; after the electric signal output by the photoelectric detector is transmitted to the peak value holding circuit for processing, the output signal is transmitted to the proportional-integral-derivative servo control module, and the output tuning voltage acts on the spectrum frequency discrimination interferometer to realize resonance frequency locking. The invention can meet the requirement of multi-longitudinal mode HSRL on the frequency stability of the spectrum frequency discrimination interferometer.
Description
Technical Field
The invention belongs to the technical field of atmospheric lidar, and particularly relates to a multi-longitudinal-mode high-spectral-resolution laser radar interferometer frequency locking system based on a peak value holding circuit.
Background
The high-spectral-resolution laser radar (High Spectral Resolution Liar, HSRL) is one of the most accurate atmospheric aerosol detection systems at present, and has the advantages that an optical filter with high spectral resolution is utilized to separate an atmospheric aerosol meter scattering signal from an atmospheric molecular Rayleigh scattering signal in an atmospheric backscattering signal, so that the characteristics of the backscattering coefficient, the extinction coefficient and the like of the aerosol are accurately inverted.
In this context, research into a new HSRL system using a multi-longitudinal mode laser is being conducted in consideration of the poor adaptability of the single longitudinal mode laser used in the current HSRL to the environment and the large volume. The principle of the multi-longitudinal mode HSRL is basically the same as that of the HSRL, namely, an interferometer frequency discriminator with a transmission curve in periodic distribution is utilized to carry out spectrum frequency discrimination on the atmospheric back scattering signal of each longitudinal mode component.
The precondition of the implementation is to ensure that the relative positions of the frequency of each laser longitudinal mode and the characteristic curve of the frequency discriminator are stable, so that the interferometer is required to be subjected to frequency locking treatment, and the frequency discrimination curve distribution of the interferometer moves along with the longitudinal modes to lock the frequency discrimination curves and the characteristic curves.
The frequency stability of the interferometer frequency discriminator adopted by the HSRL at present, such as a field-broadening Michelson interferometer, a Fabry-Perot interferometer and the like, is slightly poor, and the temperature control method is mainly adopted to keep the frequency stable. Although the method can realize long-term stability of frequency, the temperature regulation mode with slower response speed is supposed to have poor short-term stability and extremely high temperature precision requirement, so that a new frequency locking mode is needed to participate in, thereby enabling the atmosphere echo signals of all longitudinal modes to be strictly matched with the frequency discrimination curve of the device. The multi-longitudinal mode laser in the multi-longitudinal mode HSRL has a simple structure, and directly outputs pulse laser from the resonant cavity, so that the conventional continuous laser frequency locking mode is not applicable to the system.
Disclosure of Invention
The invention provides a frequency locking system of a multi-longitudinal-mode high-spectral-resolution laser radar interferometer, which improves the spectrum frequency discrimination quality when the multi-longitudinal-mode high-spectral-resolution laser radar performs atmospheric detection and simultaneously solves the control difficulty brought by the characteristic that a multi-longitudinal-mode laser directly outputs pulse light.
A multi-longitudinal mode high spectral resolution laser radar interferometer frequency locking system comprises a multi-longitudinal mode laser, a half wave plate, a polarization beam splitter prism, an acousto-optic modulation module, a spectrum frequency discrimination interferometer, a converging lens, a photoelectric detector, a peak value holding circuit and a proportion-integration-differential servo control module;
the multi-longitudinal mode pulse laser output by the multi-longitudinal mode laser is split into a high-power beam and a low-power beam by a polarization beam splitter prism after the polarization state of the multi-longitudinal mode pulse laser is adjusted by a half-wave plate, the high-power beam is used as a laser radar detection signal, and the low-power beam is used for frequency locking of a spectrum frequency discrimination interferometer;
the low-power light speed is shifted in frequency by the acousto-optic modulation module and then enters the spectrum frequency discrimination interferometer to be locked, and the light emitted from the spectrum frequency discrimination interferometer is received by the photoelectric detector after passing through the converging lens;
after the electric signal output by the photoelectric detector is transmitted to the peak hold circuit for processing, the peak hold signal and the sampling trigger signal are output to the proportional-integral-derivative servo control module, and the proportional-integral-derivative servo control module outputs tuning voltage to act on the spectrum frequency discrimination interferometer to realize resonance frequency locking.
Preferably, the acousto-optic modulation module is of a secondary modulation structure and comprises a primary acousto-optic modulator and a secondary acousto-optic modulator; the primary acousto-optic modulator is used for performing frequency shift processing on low-power light beams obtained by splitting the output of the multi-longitudinal mode laser; the secondary acousto-optic modulator is used for further frequency shifting the pulse light subjected to frequency shifting. On the premise of matching the laser with the mode, the two-stage frequency shift enables a series of laser longitudinal mode common position spectrum frequency discrimination interferometers to be in the dynamic range of the frequency discrimination curve.
Further, the peak hold circuit comprises a first-stage peak hold circuit and a second-stage peak hold circuit, wherein the first-stage peak hold circuit comprises a transconductance amplifier, a discrimination diode-hold capacitor circuit and a voltage buffer circuit; the secondary peak hold circuit comprises a voltage amplifying circuit, a discriminating diode-holding capacitor circuit, a voltage comparator, a monostable trigger circuit, a peak hold switch circuit and a voltage buffer circuit.
Because the laser pulse width in the system is of ns order and the interval between the pulses is longer, a secondary peak hold structure is adopted.
The primary peak hold circuit is used for realizing a peak hold function for a short time and expanding narrow pulses into wide pulses.
The second-stage peak value holding circuit is used for further holding the wide pulse output by the first-stage peak value holding circuit for a long time, and generating a threshold signal of fixed time when each pulse arrives, so that the holding capacitor is automatically discharged at a set time to realize a fixed peak value holding time length, and in addition, a trigger signal is generated for the AD acquisition process of the proportional-integral-differential servo control module.
The primary peak hold circuit is used for primary peak hold, the capacitance value of the adopted capacitor is smaller, internal charge can leak light in a short time, and the output hold signal is characterized by a pulse signal with longer falling time and wider pulse width compared with the original pulse.
The two-stage peak hold circuit carries out peak hold on the widened pulse in the true sense, and when the pulse peak voltage is held by utilizing the diode on-off and capacitor charging function, a peak hold threshold signal with a fixed time is generated by utilizing the voltage comparator and the monostable trigger so as to realize that the switch circuit is controlled to release the charge in the holding capacitor after the threshold signal is ended, thereby preparing for carrying out peak hold on the next pulse.
The proportional-integral-differential servo control module receives the peak hold signal and the sampling trigger signal, collects the peak hold voltage in the hold time, performs time domain averaging, obtains a calculated voltage value after proportional-integral-differential operation, performs level conversion and amplification by a peripheral circuit, and outputs continuous tuning voltage which acts on the piezoelectric ceramic module of the spectrum frequency discrimination interferometer to realize feedback control of the resonant frequency.
The proportional-integral-derivative servo module collects and averages each held voltage value for a plurality of times under the triggering of the rising edge of the signal output by the voltage comparator in the secondary peak hold circuit so as to improve the precision. Because the pulse light is detected after passing through the interferometer frequency discriminator, the peak amplitude corresponds to the relative position of each longitudinal mode and the interferometer frequency discriminator curve. When all longitudinal modes of the radar detection signal are located at the resonance point of the interferometer, all longitudinal modes of the frequency-locked light subjected to acousto-optic frequency shift are located at the edge of the interference curve, so that the voltage value acquired by the module is related to the frequency offset of the interferometer relative to the laser. Accordingly, proportional-integral-derivative operation is performed on the voltage values of a series of pulses to obtain corresponding continuous output voltages for control. The voltage is subjected to level shifting and proper amplification by a peripheral amplifying circuit to obtain the tuning voltage for enabling the frequency of the interferometer to follow the laser, so that each longitudinal mode is aligned with each resonance point of the interferometer, and the meter scattering signals in the atmospheric echo signals are accurately filtered.
The spectrum frequency discrimination interferometer is provided with a piezoelectric ceramic module, and the piezoelectric ceramic module is used for controlling the frequency of the interferometer according to the tuning voltage and comprises a piezoelectric ceramic driver and a piezoelectric ceramic displacement table; the piezoelectric ceramic driver is used for amplifying the tuning voltage in power, and the piezoelectric ceramic displacement table is used for controlling the interference arm length of the interferometer frequency discriminator.
Compared with the prior art, the invention has the following beneficial effects:
1. the system solves the problem that the traditional laser frequency locking method is not suitable for the condition of a pulse laser light source, and can meet the requirement of multi-longitudinal mode HSRL on the frequency stability of the spectrum frequency discrimination interferometer in corresponding wave bands.
2. The system has the advantages of simple equipment, low cost and low requirement on external environment, and meets the characteristics of low cost and integration of a multi-longitudinal mode HSRL system.
3. The system of the invention can be applied to other fields with high requirements on the frequency stability of the interference instrument, such as the interference detection field.
Drawings
FIG. 1 is a schematic diagram of a multi-longitudinal mode high spectral resolution laser radar interferometer frequency locking system according to the present invention;
FIG. 2 is a schematic diagram of a peak hold circuit according to the present invention;
FIG. 3 is a flow chart of the signal processing of the proportional-integral-derivative servo module according to the present invention.
Detailed Description
The invention will be described in further detail with reference to the drawings and examples, it being noted that the examples described below are intended to facilitate the understanding of the invention and are not intended to limit the invention in any way.
As shown in fig. 1, the frequency locking system of the multi-longitudinal-mode high-spectral resolution laser radar interferometer comprises a multi-longitudinal-mode laser 1, a half-wave plate 2, a polarization beam splitter prism 3, an acousto-optic modulation module 4, a spectrum frequency discrimination interferometer 5, a converging lens 6, a photoelectric detector 7, a peak value holding circuit 8 and a proportional-integral-derivative servo control module 9.
The polarization of the laser light output by the multi-longitudinal mode laser 1 is first adjusted by the half-wave plate 2, and then a beam of light is split by the polarization splitting prism 3 and is incident on the acousto-optic modulation module 4. The frequency-locked light is shifted by the acousto-optic modulation module 4, then enters the spectrum frequency discrimination interferometer 5, and the light emitted from the frequency-locked light is received by the photoelectric detector 7 after passing through the converging lens 6. The output electrical signal is first processed by a peak hold circuit 8, and the resulting trigger signal and peak-held pulse signal are transmitted to a proportional-integral-derivative servo control module 9, thereby generating a control voltage for causing the interferometer frequency to follow the laser frequency to act on the piezo-ceramic module of the spectral frequency discrimination interferometer 5.
Since the frequencies of the longitudinal modes output by the acousto-optic modulation module 4 are moved integrally relative to the output of the laser, when the frequencies of the longitudinal modes of the output light of the laser are located at the resonance point of the frequency discrimination curve of the interferometer, the longitudinal modes of the frequency-locked light are located at the edge of the frequency discrimination curve integrally. The amplitude of the frequency-locked light output from the interferometer can thus characterize the degree of frequency shift of the individual longitudinal modes before frequency shifting relative to the interferometer resonance point.
The photodetector 7 receives the frequency-locked light and outputs a narrow pulse signal. Because pulse width of pulse signal is very narrow, repetition frequency is low, typical value is 10ns, 10Hz, and normal AD sampling is difficult to accurately measure peak voltage, so that the peak hold circuit 8 is adopted to process the narrow pulse into rectangular signal, and the proportional-integral-differential servo control module 9 can accurately collect pulse peak value. In addition, the holding voltage is difficult to stabilize for a long time in the case of extremely narrow pulse width, and since the charge leakage of the capacitor has a decreasing trend, the decreasing speed is not constant in association with the pulse amplitude, and the final frequency locking effect is greatly affected, the peak hold circuit 8 here is composed of a primary peak hold section and a secondary peak hold section.
As shown in fig. 2, the first-stage peak hold firstly converts the pulse voltage output by the detector into a pulse current by using the transconductance amplifier a1, amplifies the pulse current, charges the holding capacitor a3 through the diode a2 in the forward direction of the pulse, and the capacitor charge cannot be quickly released due to the reverse turn-off of the diode, so that the pulse peak hold phenomenon occurs, and finally the capacitor voltage is buffered and output through the voltage buffer a 4. The capacitance value of the capacitor used by the first-stage peak hold circuit is smaller, and the internal charge leakage phenomenon is serious, so that the hold voltage can drop to zero faster. The primary peak hold circuit outputs a pulse signal which can be regarded as having a pulse width wider than the original pulse, and performs peak hold in a true sense by the secondary peak hold circuit.
The wide pulse signal is amplified by an operational amplifier a5, and then divided into two paths, wherein one path carries out peak value holding by using a diode a6 and a holding capacitor a7 with a larger capacitance value, and a discharge channel controlled by a field effect transistor a8 is arranged for the capacitor; the other path of input voltage comparator a9 generates a synchronous logic voltage pulse signal, the upper edge of the synchronous logic voltage pulse signal triggers the monostable trigger a10 to output a low-level threshold signal with fixed time to the grid electrode of the switching circuit field effect transistor to turn off the switching circuit field effect transistor, the field effect transistor is turned on after the threshold time is finished, and the charges in the holding capacitor are rapidly released to finish peak holding, so that the processing of the next pulse is ready. The final peak hold signal is finally output through the voltage buffer a 11.
The signal processing flow of the proportional-integral-derivative servo module is shown in fig. 3. The proportional-integral-derivative servo module 9 receives the output signal of the voltage comparator a9 in the peak hold circuit 8 and the final peak hold signal. And under the triggering of the rising edge output by the comparator, each held voltage value is acquired for a plurality of times and averaged to improve the precision. The module performs a proportional-integral-derivative operation on the voltage values of a series of pulses to obtain corresponding continuous output voltages for control. The voltage is subjected to level shifting and proper amplification by a peripheral amplifying circuit to obtain tuning voltage acting on the piezoelectric ceramic of the spectrum frequency discrimination interferometer, so that each longitudinal mode is aligned with each resonance point of the interferometer to ensure that the meter scattering signal in the atmospheric echo signal is accurately filtered.
The interferometer frequency locking system of the invention receives the pulse light of the transmission interferometer and continuously controls the signal, thereby carrying out feedback control, finally locking the resonant frequency of the interferometer to each longitudinal mode frequency of the laser, being capable of automatically compensating the frequency drift caused by environmental temperature and other reasons, having high locking precision, intelligent and rapid locking process and low cost, creating fundamental guarantee for the high stable operation of the interferometer spectrum filter in a plurality of longitudinal modes HSRL, and having great promotion effect on improving the atmospheric detection precision of the HSRL. In addition, the invention can be used for frequency locking pulse lasers for other purposes.
In the embodiment, the output wavelength of the multi-longitudinal mode laser 1 is 1064nm, and the pulse frequency is 10Hz; both stages of acousto-optic modulators use 200MHz driving to achieve 400MHz frequency offset. The spectral frequency discrimination interferometer 5 employs a field-broadening michelson interferometer that can be used for frequency locking with a dynamic range up to 1GHz. The photodetector 7 in the system is an InGaAs photodetector;
the transconductance amplifier a1 in the first-stage peak-hold circuit adopts a MAX435 chip, the diode a2 adopts a Schottky diode BAT17, and the operational amplifier a4 for buffering output adopts an OP07.
The pre-stage amplifier in the two-stage peak hold circuit adopts a wideband amplifier OPA646P, a diode a6 adopts a schottky diode BAT17, a voltage comparator a9 adopts a high-speed differential amplifier LM361, a monostable flip-flop a10 adopts 74HC123, a field effect transistor a8 adopts an N-channel enhancement type field effect transistor 2N7000, and a voltage buffer a11 adopts BUF601.
The proportional-integral-differential servo module 9 mainly comprises an STM32F103RCT6 singlechip and a peripheral circuit. STM32F103RCT6 possesses AD/DA resolution ratio of 12 bits and voltage input/output range of 0-3.3V, and peripheral circuit adopts dual operational amplifier LM358 to amplify and voltage follow the singlechip output.
In the spectrum frequency discrimination interferometer 5, the piezoelectric ceramic driver may be an E00 system of Coremorrow company, and the displacement stage of the interference arm reflector may be an XP-620 module of Coremorrow company.
The foregoing embodiments have described in detail the technical solution and the advantages of the present invention, it should be understood that the foregoing embodiments are merely illustrative of the present invention and are not intended to limit the invention, and any modifications, additions and equivalents made within the scope of the principles of the present invention should be included in the scope of the invention.
Claims (6)
1. The frequency locking system of the multi-longitudinal-mode high-spectral-resolution laser radar interferometer is characterized by comprising a multi-longitudinal-mode laser, a half wave plate, a polarization beam splitter prism, an acousto-optic modulation module, a spectrum frequency discrimination interferometer, a converging lens, a photoelectric detector, a peak value holding circuit and a proportional-integral-differential servo control module;
the multi-longitudinal mode pulse laser output by the multi-longitudinal mode laser is split into a high-power beam and a low-power beam by a polarization beam splitter prism after the polarization state of the multi-longitudinal mode pulse laser is adjusted by a half-wave plate, the high-power beam is used as a laser radar detection signal, and the low-power beam is used for frequency locking of a spectrum frequency discrimination interferometer;
the low-power light beam is shifted in frequency by the acousto-optic modulation module and then enters the spectrum frequency discrimination interferometer to be locked, and the light emitted from the low-power light beam is received by the photoelectric detector after passing through the converging lens;
after the electric signal output by the photoelectric detector is transmitted to the peak hold circuit for processing, the peak hold signal and the sampling trigger signal are output to the proportional-integral-derivative servo control module, and the proportional-integral-derivative servo control module outputs tuning voltage to act on the spectrum frequency discrimination interferometer to realize resonance frequency locking.
2. The multi-longitudinal mode high spectral resolution laser radar interferometer frequency locking system of claim 1, wherein the acousto-optic modulation module is a secondary modulation structure comprising a primary acousto-optic modulator and a secondary acousto-optic modulator; the primary acousto-optic modulator is used for performing frequency shift processing on low-power light beams obtained by splitting the output of the multi-longitudinal mode laser; the secondary acousto-optic modulator is used for further frequency shifting the pulse light subjected to frequency shifting.
3. The multi-longitudinal mode high spectral resolution lidar interferometer frequency locking system of claim 1, wherein the peak hold circuit comprises a primary peak hold circuit and a secondary peak hold circuit, the primary peak hold circuit comprising a transconductance amplifier, a discriminator diode-hold capacitor circuit, and a voltage buffer circuit; the secondary peak hold circuit comprises a voltage amplifying circuit, a discriminating diode-holding capacitor circuit, a voltage comparator, a monostable trigger circuit, a peak hold switch circuit and a voltage buffer circuit.
4. The multi-longitudinal mode high spectral resolution lidar interferometer frequency locking system of claim 3, wherein the primary peak hold circuit is configured to achieve a shorter peak hold function, stretching the narrow pulses to wide pulses;
the second-stage peak value holding circuit is used for further holding the wide pulse output by the first-stage peak value holding circuit for a long time, and generating a threshold signal of fixed time when each pulse arrives, so that the holding capacitor is automatically discharged at a set time to realize a fixed peak value holding time length, and in addition, a trigger signal is generated for the AD acquisition process of the proportional-integral-differential servo control module.
5. The multi-longitudinal mode high spectrum resolution laser radar interferometer frequency locking system according to claim 1, wherein the proportional-integral-derivative servo control module receives the peak hold signal and the sampling trigger signal, collects the peak hold voltage in the holding time and performs time-domain averaging, obtains a calculated voltage value after the proportional-integral-derivative operation, performs level conversion and amplification by a peripheral circuit, and outputs continuous tuning voltage, and the continuous tuning voltage is applied to the piezoelectric ceramic module of the spectrum frequency discrimination interferometer to realize feedback control of the resonant frequency.
6. The multi-longitudinal mode high spectral resolution laser radar interferometer frequency locking system according to claim 1, wherein the spectral frequency discrimination interferometer is provided with a piezoelectric ceramic module, and the piezoelectric ceramic module is used for controlling the frequency of the interferometer according to the tuning voltage and comprises a piezoelectric ceramic driver and a piezoelectric ceramic displacement table; the piezoelectric ceramic driver is used for amplifying the tuning voltage in power, and the piezoelectric ceramic displacement table is used for controlling the interference arm length of the interferometer frequency discriminator.
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| CN103368053A (en) * | 2013-07-30 | 2013-10-23 | 哈尔滨工业大学 | LD (Laser Diode) pumping single frequency pulse 1645nm solid laser |
| CN106019312A (en) * | 2016-08-04 | 2016-10-12 | 浙江大学 | Multi-longitudinal-mode high-spectral-resolution lidar based on interference spectrum frequency detector |
| CN106019259A (en) * | 2016-07-11 | 2016-10-12 | 中国科学院上海技术物理研究所 | Laser frequency discriminating device and frequency discrimination method based on Mach-Zehnder interferometer |
| CN109378681A (en) * | 2018-11-08 | 2019-02-22 | 中国人民解放军国防科技大学 | Cascade frequency shift-based high-average-power mode-locked laser generation system and method |
| CN109556591A (en) * | 2018-11-22 | 2019-04-02 | 华中科技大学 | A kind of passive type lasergyro based on super stabilized laser |
-
2020
- 2020-09-02 CN CN202010909864.0A patent/CN112180394B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103368053A (en) * | 2013-07-30 | 2013-10-23 | 哈尔滨工业大学 | LD (Laser Diode) pumping single frequency pulse 1645nm solid laser |
| CN106019259A (en) * | 2016-07-11 | 2016-10-12 | 中国科学院上海技术物理研究所 | Laser frequency discriminating device and frequency discrimination method based on Mach-Zehnder interferometer |
| CN106019312A (en) * | 2016-08-04 | 2016-10-12 | 浙江大学 | Multi-longitudinal-mode high-spectral-resolution lidar based on interference spectrum frequency detector |
| CN109378681A (en) * | 2018-11-08 | 2019-02-22 | 中国人民解放军国防科技大学 | Cascade frequency shift-based high-average-power mode-locked laser generation system and method |
| CN109556591A (en) * | 2018-11-22 | 2019-04-02 | 华中科技大学 | A kind of passive type lasergyro based on super stabilized laser |
Non-Patent Citations (2)
| Title |
|---|
| 基于法布里－珀罗干涉仪的激光谱线特性测量研究;王彬宇 等;《物理实验》;全文 * |
| 多纵模高光谱分辨率激光雷达研究;成中涛 等;《光学学报》;全文 * |
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