42 results about "Frequency shifter" patented technology

The application discloses a microwave photon frequency hopping signal generation device and method based on an optical switch and belongs to the technical field of optical communication. The application is composed of a light source, a beam splitter, an optical frequency comb generator, an electro-optical frequency shifter, an acousto-optic modulator, a digital frequency synthesizer, a filter array, a signal control unit, an electrically controlled high-speed optical switch, a beam combiner and a photoelectric detector. The application separates optical frequency comb teeth by using an ultra-narrow bandwidth optical filter, selects and opens the frequency hopping signal generated by the local light beat frequency through the optical switch, and can generate a high-speed high-order high-stability frequency hopping signal compared with the prior art.

The invention discloses a photoacoustic stimulated Raman gas detection system and method based on hollow-core optical fiber self-seed injection enhancement, and belongs to the technical field of laser spectrum trace gas detection, the system comprises a light source and beam splitting module, a hollow-core optical fiber seed generation module, a light delay module and a short optical path power amplification module; the main laser beam is split into a first light beam and strong pump light after entering the beam splitter; in the hollow-core optical fiber seed generation module, a first light beam passes through a fifth reflecting mirror, a hollow-core optical fiber seed generation unit, a sixth reflecting mirror and an optical filter, and weak seed light is output; the strong pump light is synchronized with the weak seed light output from the optical filter after entering the optical delay module; in the short-optical-path power amplification module, weak seed light and strong pump light output by the light delay module are combined at a dichroscope and are strictly coaxial, and then are focused by a convex lens and enter a short-optical-path Raman frequency shifter. According to the invention, the oscillation starting threshold of the Raman frequency shifter is greatly reduced by utilizing seed light-induced stimulated radiation.

The invention provides a spectrum testing method for electro-optical modulation signals. The device is composed of a laser, a microwave signal source, a to-be-measured electro-optical modulation signal generation module, an optical frequency shifter, an electro-optical phase modulator, a photoelectric detector and a spectrum analysis module, optical signals output by the laser are divided into two paths, the upper path is in optical connection with the to-be-measured electro-optical modulation signal generation module, and the lower path is in optical connection with the to-be-measured electro-optical modulation signal generation module. The lower path is sequentially and optically connected with the optical frequency shifter and the electro-optic phase modulator and is optically connected with the photoelectric detector after being combined, the microwave signal source is electrically connected with the radio frequency end of the electro-optic phase modulator, and the output end of the photoelectric detector is electrically connected with the spectrum analysis module. Heterodyne mixing signals f1-pf2 (p is a positive integer) of an electro-optical modulation spectrum signal f1 to be detected and an electro-optical phase modulation signal f2 are detected, mixing signal power ratios when output signal voltages of a microwave signal source are V2 and kV2 respectively are analyzed, the p value and the frequency f1 are determined by utilizing the Bessel function relation, meanwhile, the frequency response of a photoelectric detector is calibrated, and the frequency response of the photoelectric detector is calibrated. The relative amplitude of each order of light modulation sideband of the electro-optical modulation spectrum to be tested is obtained, and spectrum testing of the electro-optical modulation signal to be tested is achieved.

The application relates to the technical field of electro-optical frequency comb generation, and discloses a super-narrow-line-width, wide-band, flexible-repetition-frequency and adjustable electro-optical comb generation system and method, which comprises a pump laser generation branch, a fiber ring cavity, and a frequency shift injection locking branch.The pump laser generation branch comprises a distributed feedback laser, a first polarization controller and a first circulator; the fiber ring cavity comprises a second circulator, a Brillouin gain fiber, a fiber delay line, a fiber coupler, a second polarization controller, an electro-optical modulator, a dispersion compensation fiber, an optical amplifier, a flat filter and an isolator; and the frequency shift injection locking branch comprises a narrow-bandwidth filter, a polarization controller and a frequency shifter.The electro-optical frequency comb generation device of the application has a novel structure, realizes super-narrow-line-width, wide-band, flexible-repetition-frequency and adjustable electro-optical comb output, solves the limitations of narrow bandwidth and wide comb line width of a traditional electro-optical frequency comb generated based on electro-optical modulation, and does not need complex active optoelectronic feedback to maintain stable operation of the system.

The invention relates to a pure Rayleigh scattering signal acquisition method and system based on a laser source. The method comprises the following steps: performing beam splitting treatment on femtosecond pulses output by a laser source to obtain at least two beams of femtosecond pulses; inputting the first beam of femtosecond pulse into a nonlinear crystal for frequency mixing processing to obtain a preprocessed scattering signal; performing frequency shift processing on the second beam of femtosecond pulse by using an acousto-optic frequency shifter or performing phase lock processing on the second beam of femtosecond pulse by using an optical phase lock ring to obtain a coherent local oscillator signal; inputting the preprocessed scattering signal and the coherent local oscillator signal into a frequency mixer for interference processing to obtain a mixed difference frequency signal; and performing multi-stage signal processing on the mixed difference frequency signal by using a signal processor to obtain a target Rayleigh scattering signal. According to the invention, the Rayleigh scattering signal acquisition accuracy can be improved.

This invention discloses a photoacoustic stimulated Raman gas detection system and method based on hollow-core optical fiber seed injection enhancement, belonging to the field of laser spectroscopy trace gas detection technology. The system includes a light source and beam splitting module, a hollow-core optical fiber seed generation module, an optical delay module, and a short-path power amplification module. The main laser beam is incident on a beam splitter and splits into a first beam and a strong pump beam. In the hollow-core optical fiber seed generation module, the first beam is reflected by a fifth mirror, a hollow-core optical fiber seed generation unit, a sixth mirror, and a filter, outputting a weak seed beam. The strong pump beam enters the optical delay module and synchronizes with the weak seed beam output from the filter. In the short-path power amplification module, the weak seed beam and the strong pump beam output from the optical delay module are combined and strictly coaxial at a dichroic mirror, then focused by a convex lens and enter the short-path Raman frequency shifter. This invention achieves a significant reduction in the oscillation threshold of the Raman frequency shifter by utilizing seed light-induced stimulated emission.

The invention discloses a communication and remote sensing integrated forest fire prevention laser radar system and a use method thereof. The laser radar comprises a continuous light laser, a beam splitter, an analog signal generator, an electro-optical modulator, a pulse optical fiber amplifier, a circulator, a variable-focus transceiver telescope, a coupler, an acousto-optic frequency shifter, a balance detector, a receiving telescope, an avalanche diode detector, a multi-channel data acquisition system and a computer. According to the invention, the electro-optical modulator is adopted to modulate a high-frequency pulse signal, and an atmospheric detection signal and a communication signal can be generated; signal frequency shift is realized by adopting an acousto-optic frequency shifter, and wind field direction information is obtained; a variable-focus transceiving telescope, a receiving telescope and laser radars are adopted for networking, and optical information transmission between the laser radars is achieved. The system can realize information communication of the laser radar in a non-signal area, and is especially suitable for being applied to the field of forest fire prevention based on the advantages of multi-parameter detection, high resolution and wide coverage of the laser radar.

Disclosed is a transmit-receive coaxial phased array LiDAR chip and a control method. The transmit-receive coaxial phased array LiDAR chip includes a laser transmitter unit, a main beam splitter, a transmit-receive phased array, a balanced detector array, and a signal processing and control unit. Phase modulation is performed on optical signals, and the optical signals are split into reference light and signal light. The signal light is radiated into a free space. The reference light passes through a frequency shifter and is input into a 90-degree optical mixer with an echo signal to generate a beat signal. The balanced detector array receives the beat signal, converts the beat signal into an electrical signal, and transmits the electrical signal to the signal processing and control unit. The signal processing and control unit calculates three-dimensional depth information and / or velocity information of a target region based on the electrical signal.

This invention discloses a laser linewidth measurement device and method based on switchable channel delay self-heterodyne interferometry, belonging to the field of laser linewidth measurement technology. The laser to be measured is incident on a first fiber coupler via an isolator and splits into two paths: one path enters a computer-controlled first and second optical switches via a three-port fiber circulator, switching between different lengths of delay fiber via the first and second optical switches, rotating the polarization state by 90° via a Faraday rotating mirror before returning along the original path, and then restoring the original polarization state via a polarization controller; the other path undergoes frequency shifting via an acousto-optic frequency shifter. The two paths are combined via a second fiber coupler to generate a beat frequency optical signal, which is then acquired by a photodetector for photoelectric conversion and a spectrum analysis module. The computer fits the beat frequency power spectrum corresponding to different delay lengths to obtain the laser linewidth to be measured. This invention has strong anti-interference capabilities and can simultaneously acquire Lorentz linewidth, Gaussian linewidth, and composite linewidth, with a wide linewidth measurement range.

The utility model discloses a wind measurement radar device based on a silicon-based photoelectronic technology, and relates to the field of laser wind measurement. The wind measurement radar device comprises a receiving and transmitting integrated module based on the silicon-based photoelectronic technology, an acousto-optic frequency shifter, an optical amplifier, a circulator, a wavelength division multiplexer and an optical antenna, wherein the acousto-optic frequency shifter is connected between the receiving and transmitting integrated module and the optical amplifier; the optical amplifier is connected to the circulator, the circulator is in dual-phase connection with the wavelength division multiplexer, the circulator is connected to the optical transceiving integrated module, and the optical transceiving integrated module comprises an adjustable narrow linewidth laser based on the silicon-based photoelectron technology, a balance detector, a frequency mixer, an optical splitter, an optical fiber array, a sealing tube and the like. According to the utility model, the tunable narrow linewidth laser adopting the silicon optical external cavity scheme is matched with the pure solid state scheme of the wavelength division multiplexer, so that the process of switching an optical antenna by using an optical switch in the measurement process is directly avoided; line width performance indexes of the laser can be far better than that of a traditional adjustable laser of an InP-based platform through design and process optimization.

An optical device having a frequency shifter, the frequency shifter having an optical component having a phase modulator having a silicon material substrate, a buried oxide layer disposed on the silicon material substrate, a silicon waveguide disposed on the buried oxide layer, wherein the silicon waveguide is configured to guide a light, and a pair of electrodes disposed on the silicon waveguide, wherein the phase modulator is configured to change the phase of the light passing through it, and an electronic drive circuit in electrical communication with the phase modulator such that the phase change is linearly proportional to time. The disclosed optical device is configured to provide optical frequency shifting capabilities to and be integrated within silicon photonics-based devices, wherein the disclosed optical device is configured to facilitate this frequency shifting capability while being compact and having a low cost.

The utility model discloses a heterodyne Doppler laser vibration meter based on all optical fibers. The vibration meter adopts a double-light-path differential design, and the system divides laser into a measuring light beam and a reference light beam which are respectively guided into a measuring light path and a reference light path which are parallel to each other. The measuring light path emits laser to an object to be measured, and a return signal of the laser comprises composite information of object vibration and system errors after being demodulated. Meanwhile, a reference light path forms a closed loop inside, and a demodulation signal of the reference light path can accurately extract system errors introduced by devices such as a frequency shifter. The signal processing system subtracts the two demodulated signals in real time, so that homologous errors are eliminated, and pure and real vibration data are obtained. According to the utility model, a complex phase-locked loop is replaced by front-end optical path difference, so that the measurement precision, stability and environmental adaptability are remarkably improved.

The application belongs to the technical field of optical fiber measurement, and particularly relates to an optical frequency domain polarimeter of polarization beam splitting structure frequency shift detection with ultra-high sensitivity, which comprises a tunable laser source module, a device to be measured module, a polarization beam splitting frequency shift interferometer module, an auxiliary interferometer module and a signal acquisition and analysis module, and is characterized in that: a frequency shifter contained in the polarization beam splitting frequency shift interferometer module is used to move the signal to a high frequency, thereby avoiding the noise aliasing problem from a low frequency; a polarization beam splitter is used to separate the transmission mode and the coupling mode light passing through the device to be measured to suppress the main interference peak, thereby improving the sensitivity to-130 dB, and greatly improving the speed and sensitivity of the polarization crosstalk measurement in principle. Meanwhile, the main extended optical fiber and the acousto-optic modulator are combined to shift the signal, thereby meeting the acquisition of the polarization crosstalk information when the long-distance device is tested.

The application discloses a kind of narrow line width fiber laser systems based on active phase compensation of fiber loop interferometer frequency stabilization, comprising: fiber laser, the laser is sequentially connected with first frequency shifter, Y type coupler, X type coupler and photoelectric detector by conducting optical fiber and constitutes loop interferometer loop.The photoelectric detector is connected with radio frequency power divider, and also be used to convert beat frequency optical signal output by fiber loop interference loop into radio frequency electric signal;The output end of the radio frequency power divider is respectively connected with first feedback calibration loop and second feedback calibration loop, to carry out the fast feedback calibration of laser frequency by first feedback calibration loop, and carry out the active compensation of delay optical fiber phase noise by second feedback calibration loop.And by second proportional integral amplifier for slow feedback calibration of laser frequency.The interferometer frequency stabilization system presented in the application has high detection sensitivity and large bandwidth, and has lower environmental sensitivity.

The application discloses a kind of spatial filtering type differential resonance photoacoustic stimulated raman detection systems and methods, belong to gas detection technical field, the system includes laser source module, raman frequency shifter module, spatial filtering type differential resonance photoacoustic cell and signal acquisition and processing unit;High-energy pulsed laser generated by laser source module is shot into raman frequency shifter module after collimation;The double-color coherent light beams output by raman frequency shifter module are focused after achromatic lens, and are coaxially shot into the center of spatial filtering type differential resonance photoacoustic cell, and the photoacoustic signals excited are collected by two microphones of spatial filtering type differential resonance photoacoustic cell;Signal acquisition and processing unit is electrically connected each microphone;Two acoustic tubes of spatial filtering type differential resonance photoacoustic cell are symmetrically arranged in the inside of large tube buffer cavity, and two Brewster windows are respectively sealed and installed at the two ends of large tube buffer cavity.The application can effectively inhibit window optical damage, improve system stability.

A measurement device includes a splitter splitting light from a light source into first and second lights; an optical frequency shifter shifting a frequency of the first light; a first optical modulator modulating intensity of the first light and generating probe light having two frequency components; a second optical modulator generating pump light by pulsing the second light; an optical detector detecting, when the probe light is incident from a first end of an optical fiber to be measured and the pump light is incident from a second side of the optical fiber, light emitted from the second side of the optical fiber; and a processor measuring, based on detected light intensity, temperature or distortion of the optical fiber, in which a frequency of a lower one of the two frequency components yields Brillouin gain, and a frequency of a higher frequency component yields Brillouin loss.

The application discloses a high-sensitivity vibration sensing system and method using a broadband light source, wherein after broadband light passes through a fiber grating, the spectrum width of the light source is compressed, the coherence length is controlled, and two beams of light with an optical path difference within a specific range interfere, so that the noise of the sensing system can be significantly reduced; a heterodyne modulation and demodulation method is adopted, a fiber delay module and an acousto-optic frequency shifter are introduced into a reference path, the fiber length is compensated by controlling the cavity length, the high-order reflected detection light in the fiber Fabry-Perot resonant cavity interferes with the first-order reflected reference light, and the effect of improving the sensitivity is achieved. The application utilizes the advantages of the spectrum width of the broadband light source and the wavelength characteristics of the fiber grating, and realizes the dynamic signal modulation and demodulation of the broadband light source heterodyne interference with the advantages of reusability, high sensitivity and low cost.

The application discloses a full-fiber unmodulated frequency discriminator with long absorption spectrum, which is used for obtaining an error electric signal capable of indicating the relative central frequency deviation of the current output frequency of a laser, and can be applied to a laser frequency stabilization system. The frequency discriminator is based on the gas chamber absorption spectrum difference principle, and comprises a laser to be stabilized, a frequency shifter, a gas chamber, a balanced detector and a transmission optical fiber. The frequency discriminator realizes double gas absorption spectrum while saving cost and reducing the system volume through the internal optical structure design. The frequency discriminator has simple structure and is easy to integrate. The process of obtaining the error electric signal does not need modulation and demodulation, and high frequency discrimination sensitivity is realized through long absorption spectrum.

The present disclosure relates to a system and method of providing multiple bandwidth support by incorporating one additional frequency shifter in a Field Programmable Gate Array (FPGA) platform while re-using available base band design with single Fast Fourier Transform (FFT) size. This method facilitates to save FPGA resources and provides additional sampling in lower bandwidth configurations leading to common sampling rate for all bandwidths which further simplifies an end-to-end design. Further, the method discloses an efficient way of implementing a frequency shifter in the FPGA platform.

The invention discloses a PDH laser frequency locking system for generating sidebands based on a nonlinear SOA. The PDH laser frequency locking system comprises a seed laser source, a first coupler, a second coupler, a first acousto-optic frequency shifter, a second acousto-optic frequency shifter, a semiconductor optical amplifier, a circulator, a reference cavity, a photoelectric detector, a frequency mixer, a demodulation filtering module and a servo controller. A nonlinear SOA is used for replacing a traditional electro-optical modulator to efficiently generate a multi-sideband signal needed by PDH frequency locking, the system cost and complexity are remarkably reduced, and the flexibility and strength of sideband generation are improved; meanwhile, through the collaborative design of the double acousto-optic frequency shift and the SOA nonlinear effect, accurate matching of the sideband frequency interval and the free spectral range of the reference cavity is achieved, and the signal-to-noise ratio and the frequency locking stability of the PDH error signal are greatly improved.

The invention provides a single-period oscillation microwave signal generation device and method based on frequency shift light injection locking, and relates to the technical field of microwave photonics. The device comprises a master laser, a first optical circulator, an optical attenuator, a first polarization controller, a second optical circulator, a slave laser, an optical fiber amplifier, a second polarization controller, a Brillouin ring cavity, a second optical fiber coupler, a photoelectric detector, an optical frequency shifter, an optical filter and a third polarization controller. Light emitted by the master laser is injected into the slave laser to generate a single-period oscillation optical signal, the single-period oscillation optical signal is input into the Brillouin cavity to generate Brillouin laser and is divided into two paths, and one path is subjected to photoelectric conversion to generate a microwave signal; and the other path is injected into the master laser after passing through the optical frequency shifter so as to lock the master laser, and then is injected into the slave laser by the master laser so as to lock the single-cycle oscillation optical signal. According to the invention, a stable single-frequency microwave signal can be output, and the advantages of low phase noise, high side-mode rejection ratio and wide tuning range are achieved.

The application provides a kind of distributed optical fiber acoustic sensor, comprising: narrow line width laser, pulse light modulator, erbium-doped fiber amplifier, circulator, filter, photodetector, analog-to-digital converter, demodulation system and fluorescent optical fiber;Fluorescent optical fiber is doped with fluorescent substance in the core;Narrow line width laser is modulated into pulse light after emitting continuous laser, and the pulse light enters the circulator through the first port after passing through erbium-doped fiber amplifier and is injected into fluorescent optical fiber through the second port;Pulse light excites fluorescent substance to produce fluorescence, and the fluorescence returned along the fluorescent optical fiber forms fluorescent back light;The pulse light injected into the fluorescent optical fiber produces back Rayleigh scattering light;Fluorescent back light and back Rayleigh scattering light beat in the fluorescent optical fiber, forming beat signal.The distributed optical fiber acoustic sensor provided by the application is based on the similar structure as the direct detection method, realizes coherent detection, does not need frequency shift device and coupler, simplifies the device structure, and improves the sensor quality.

The invention discloses a compact low-frequency resonance opto-acoustic Raman detection system and method based on hollow-core optical fiber enhancement, and belongs to the technical field of gas detection.In the system, low-energy and high-frequency pulse laser generated by a high-repetition-frequency and low-energy laser source module is focused by a convex lens and then enters a hollow-core optical fiber Raman frequency shifter module; after being collimated by an achromatic collimating lens, two-color coherent light beams output by the hollow-core optical fiber Raman frequency shifter module are coaxially emitted into the spiral connection tube type low-frequency resonance photoacoustic cell, and excited resonance photoacoustic signals are collected by a first microphone arranged in a signal cavity of the spiral connection tube type low-frequency resonance photoacoustic cell and a second microphone arranged in a reference cavity of the spiral connection tube type low-frequency resonance photoacoustic cell; and the signal acquisition and processing unit is electrically connected with the first microphone and the second microphone and is used for performing differential phase locking processing and concentration inversion on the acquired resonance photoacoustic signals to obtain the concentration value of the gas to be detected. According to the invention, precise locking of the laser repetition frequency and the acoustic resonance frequency and high-Q-value resonance amplification of the photoacoustic signal are realized.

The invention discloses a radar multi-pattern interference signal generation method based on a photon radio frequency memory, and relates to the technical field of radar countermeasure. According to the method, a laser device LD, a dual-polarization quadrature phase shift keying modulator DPQPSK, an arbitrary waveform generator AWG, a vector signal generator VSG, an electrical 90-degree coupler 90-degree HC, a polarization controller PC, a polarizer Pol, an optical switch OS, an optical delay line ODL, an adjustable optical delay line TODL, a 2 * 2 optical coupler OC, an optical band pass filter OBPF, an acousto-optic frequency shifter AOFS, a photoelectric detector PD and an erbium-doped fiber amplifier EDFA are included. According to the invention, Doppler modulation is introduced to a signal by using DPQPSK, the state of an OS in a cascade optical delay loop is regulated and controlled by changing a control signal time sequence, the cycle index and delay amount of an optical signal are controlled, and an interference signal with adjustable delay length, delay resolution, Doppler frequency and false target number is generated. Flexible and tunable large instantaneous bandwidth real-time speed, distance, dense false targets, suppression and imaging interference are realized.

The application discloses a kind of based on mode multiplexing resonator's dual optical frequency comb generation system and method, system includes continuous light laser, first optical coupler, second optical coupler, third optical coupler, acoustooptic frequency shifter, first mode coupler, second mode coupler, third mode coupler, fiber ring resonator;Fiber ring resonator is by first mode coupler, second mode coupler, third mode coupler and few-mode fiber constitute;By above system, single base mode transmission is changed into the coupling transmission of high-order mode and base mode in cavity, to generate optical frequency comb respectively, and merge into dual optical frequency comb.The system uses the exchange of mode to avoid the excessive accumulation of the speed difference of two modes of fiber ring of fiber ring resonator, so that the light of two paths has different loop time, and by controlling the length difference of two optical fibers of fiber ring resonator, the dual optical frequency comb with the required repetition frequency difference is obtained.The scheme of the application has simple structure, is easy to manufacture, low in cost and has wide application prospect.

The invention discloses a temperature-insensitive silicon-based hybrid integrated active optical frequency laser regeneration relay chip, which is suitable for a photon integrated optical frequency cascade transmission system. The chip can carry out on-chip regeneration amplification on a received previous-stage optical signal, and outputs an optical frequency signal with a stable phase to a next stage. According to the invention, the low-loss passive silicon-based waveguide is extremely low, and strict length matching is carried out on the out-of-band waveguide path in the chip, so that out-of-band phase noise caused by temperature change can be effectively inhibited, and the environmental adaptability of the chip is improved. Meanwhile, by means of advanced processes such as micro transfer printing, heterogeneous hybrid integration is carried out on a high-efficiency on-chip frequency shifter and a polarization controller which are realized on the basis of high-electro-optical coefficient materials such as thin-film lithium niobate, so that the on-chip optical frequency laser regeneration relay chip with complete functions is constructed. The chip has the advantages of being compact in structure, low in power consumption, high in environmental adaptability and the like, and is suitable for construction of a next-generation miniaturized optical frequency transfer network.

An optical beam transmission device incudes: a light distributor to split a laser beam; an optical frequency shifter to shift a frequency of the local light beam; a collimating lens to convert the local light beam; an optical phase shifter to change a phase of a corresponding transmission light beam; an optical modulator to modulate a transmission light beam; an optical amplifier to amplify intensity of the transmission light; an optical collimator array to convert the transmission light beam after amplification; an optical beam splitter to split and synthesize some of the transmission beams to obtain synthesized phase monitoring light; a photoelectric converter to photoelectrically convert corresponding synthesized phase monitoring light; a modulated electrical signal outputter to output a modulated electrical signal having a controlled delay time; and an optical phase synchronization controller to detect a phase of an electrical signal and output a control signal.

The invention relates to an on-chip integrated multi-frequency narrow-linewidth semiconductor laser optical pulse device and a preparation method thereof. The device comprises a silicon substrate; the laser signal processing device is positioned on the silicon substrate and is processed and prepared through a semiconductor technology; the laser signal processing device comprises a silicon-based waveguide grating, a silicon-based optical switch structure, a silicon-based frequency shifter structure and a silicon-based beam combining structure which are connected in sequence; the single-mode output semiconductor laser is processed and prepared through a semiconductor technology and connected to the silicon substrate through heterogeneous bonding, the waveguide structure is a single-mode waveguide, the semiconductor laser is connected to the silicon substrate through heterogeneous bonding, and the semiconductor laser is coupled with the silicon-based waveguide grating through an end face. The method comprises the following steps: preparing a laser signal processing device; processing and preparing a semiconductor laser through a semiconductor technology; the two devices are placed on a silicon substrate. According to the invention, external elements are not needed, the loss of light in the transmission process is small, and the process complexity is not improved in the packaging process.

The invention discloses a laser vibration measurement analysis method based on an autocorrelation algorithm, and belongs to the technical field of laser high-precision detection. According to the method, the structure of a laser Doppler measurement system is optimized, and a typical phase modulation signal is generated by simultaneously driving an acousto-optic frequency shifter through a trigger signal and mixing the acousto-optic frequency shifter with a photocurrent signal after AD sampling. The phase change frequency of a modulation signal is directly analyzed by using an autocorrelation algorithm, the target vibration frequency is obtained, and complex processes such as orthogonal carrier generation, phase unwrapping and FFT transformation in a traditional method are avoided. In order to solve the problem that self-correlation may only demodulate even harmonics, a delay comparison step is introduced to ensure the uniformity of odd-even harmonic identification. According to the invention, the working process of the system is obviously simplified, the realization difficulty and cost of the laser Doppler vibration measurement technology are reduced, and the analysis efficiency and robustness are improved.

The invention provides a point diffraction interferometer, comprising: a laser (100) suitable for generating collimated laser; the frequency shifting assembly (200) comprises a first acousto-optic frequency shifter (201) which is suitable for enabling the collimated laser to generate diffraction and obtaining two beams of first sub-laser with a frequency difference; the second acousto-optic frequency shifter (202) is matched with the first acousto-optic frequency shifter (201), so that the two beams of first sub-laser with the frequency difference are diffracted respectively, and two beams of second sub-laser which are parallel and have the frequency difference are obtained; a diffraction assembly (300) configured to diffract the two beams of second sub-laser to generate reference light with a spherical wave front and measurement light with the spherical wave front; wherein the measuring light is reflected by the to-be-measured element after entering the to-be-measured element, and reflected light carrying surface shape information of the to-be-measured element (600) is obtained; and the interference assembly (400) is matched with the diffraction assembly (300) and is suitable for enabling the reference light and the reflected light to generate interference to obtain an interference signal, and the interference signal is used for determining the surface shape information of the element to be detected.