323 results about "Acousto-optic modulator" patented technology

Disclosed herein is an optical frequency comb generator for a distributed acoustic anomaly detection system. The system can include a continuous wave frequency modulated laser source configured to generate a laser signal. The system can include an acousto-optical modulator configured to modulate the laser signal by altering an amplitude and / or frequency of the laser signal based on an RF drive signal applied to the AOM, and to output an optical pulse with multiple frequency sidebands based on the modulation. The output can form an optical frequency comb usable detecting and locating acoustic anomalies within a structure under observation.

The invention discloses acousto-optic chalcogenide glass with a high laser damage threshold, the chemical composition formula of the acousto-optic chalcogenide glass is GexSySez, x, y and z respectively represent the mole fractions of Ge, S and Se, x = 10-30, y = 5-40, z = 40-70, x + y + z = 100, and the microscopic network structure of the acousto-optic chalcogenide glass contains a [GeSe4] tetrahedron, a [GeSSe3] tetrahedron, a [GeS2Se2] tetrahedron, a [GeS3Se] tetrahedron, a [GeS4] tetrahedron and a Se ring. The acousto-optic chalcogenide glass provided by the invention has a relatively high laser damage threshold Fth (9.72-15.58 J / cm < 2 > at1550 / 20ns / 5kHz), a relatively low thermo-optic coefficient dn / dT and good acousto-optic characteristics and mechanical properties, is high in near-infrared band transmittance, and has a relatively high laser damage threshold while ensuring a high acousto-optic quality factor. The material can be used as a material basis for developing high-performance and high-stability infrared acousto-optic modulation devices.

The invention discloses a high-power picosecond pulse train laser with programmable sub-pulse energy and a method, and relates to the related technical field of lasers, the high-power picosecond pulse train laser comprises a mode-locked fiber laser, an acousto-optic modulator and a solid amplification chain which are sequentially arranged along an optical transmission path; the mode-locked fiber laser generates a mode-locked picosecond pulse sequence; the acousto-optic modulator performs pulse selection and pulse string grouping on the mode-locked picosecond pulse sequence, and performs pre-programming shaping on sub-pulse energy in a pulse string according to set intensity distribution to generate a pre-shaped pulse string; the solid amplification chain comprises at least one stage of solid amplifier, and the solid amplifier comprises a dichroscope, a laser gain crystal, a coupling optical assembly and an LD pumping source; and the dichroscope is used for focusing the pre-shaped pulse string amplified at the previous stage and the LD pump light transmitted by the coupling optical assembly into the laser gain crystal. Independent programmable regulation and control of the energy of each sub-pulse in the pulse string are realized, and the energy distribution of each sub-pulse in the pulse string can be flexibly adjusted.

The invention provides a dual-mode gravitational acceleration precision measurement system and method based on a light floating effect. According to the system, a 1064nm laser double-beam correlation structure is adopted, a strong focusing light trap is formed in a gravity orthogonal direction, and micron-sized silicon dioxide particles are stably captured. In the absolute measurement mode, the acousto-optic modulator is used for controlling the on-off of the laser, the high-speed position detection module is used for detecting and recording the free falling motion trail of the particles and the displacement amplitude showing the resonance state after re-capturing, and the absolute gravitational acceleration parameter is inverted. In a relative measurement mode, weak focusing 532nm laser is configured along the gravity direction to construct a gravity compensation light trap, and after absolute gravitational acceleration reference measurement is completed, the laser is modulated by an acoustic optical modulator to accurately balance the gravity of particles, so that the particles enter a quasi-balance state. When the external gravitational field changes slightly, the characteristic displacement of the particles in the gravity direction is extracted, and the change of the relative gravitational acceleration can be monitored continuously.

This invention relates to a Bragg light generation system and method suitable for Bragg-type atomic interferometers. The system includes: a laser for generating a first laser beam with a frequency in a preset atomic absorption peak band; an optical circulator for propagating the first laser beam to a cascaded acousto-optic modulator and receiving two third laser beams returned from the cascaded acousto-optic modulator; a cascaded acousto-optic modulator for diffracting the first laser beam into two second laser beams with opposite propagation directions through Bragg diffraction of two acousto-optic crystals; an optical assembly for performing secondary diffraction on the two second laser beams and reflecting the two mutually perpendicular second laser beams to the cascaded acousto-optic modulator; and an output module for splitting and sampling the two third laser beams and modulating the sampled third laser beams into Bragg laser beams in the target frequency band. This invention reduces the path separation of the two Bragg laser beams by using a quasi-common optical path, thereby reducing phase noise and improving measurement accuracy.

The utility model discloses a distributed sound wave sensing system for multi-frequency pulse modulation, and relates to the technical field of distributed sound wave sensing. The system comprises a narrow linewidth laser, an optical fiber coupler, a polarization-maintaining optical isolator, an acousto-optic modulator, a polarization-maintaining delay optical fiber, an erbium-doped optical fiber amplifier, a polarization-maintaining dense wavelength division multiplexer, an optical fiber circulator, an optical fiber Bragg grating, a piezoelectric transducer, a polarization controller, a photoelectric balance detector, a data acquisition card, an arbitrary waveform generator and the like. According to the utility model, the multi-frequency delay ring is utilized to carry out multi-frequency modulation, the frequency number of light waves is increased along with the circulation times of the light waves in the delay ring, and under the condition that the utilization of a large-bandwidth electro-optical modulator is not increased, the flexible modulation of the frequency is realized by utilizing a low-bandwidth acousto-optical modulator without being influenced by carrier frequency and sidebands of each order; the low-bandwidth acousto-optic modulator is used for frequency modulation in the multi-frequency delay ring, and compared with an electro-optical modulation or multi-acousto-optic / multi-light source modulation scheme, the modulation cost is effectively saved.

The invention discloses a distributed optical fiber two-dimensional vector sensing system and method, the system uses an acousto-optic modulator group and an optical circulator group to ask a plurality of fiber cores of a multi-core optical fiber in parallel, heterodyne coherent detection uses local oscillator light to improve the signal-to-noise ratio, and through the relation between the fiber core position difference and the direction angle of a two-dimensional sound wave in the aspect of algorithm, the two-dimensional sound wave direction angle is obtained. According to the space division multiplexing distributed optical fiber acoustic sensing system, a two-dimensional vector signal is accurately restored, the measurement vector angle range of the space division multiplexing distributed optical fiber acoustic sensing system for two-dimensional sound waves is 0-360 degrees, the vector sensing range is larger than 50 km and far exceeds that of an existing system, and the detection capacity of the distributed optical fiber acoustic sensing system is greatly improved.

The present invention relates to a high-speed, high-threshold acousto-optic modulator based on lithium niobate, belonging to the field of optoelectronics; the acousto-optic modulator comprises an acousto-optic medium, a bonding layer, a transducer and a surface electrode; the sound-transmitting surface of the acousto-optic medium is equipped with a transducer through the bonding layer, and the surface electrode is plated on the surface of the transducer; the acousto-optic medium is a lithium niobate crystal, the [100] axis of the lithium niobate crystal is perpendicular to the sound-transmitting surface of the acousto-optic medium, the [010] axis of the lithium niobate crystal is located within the sound-transmitting surface of the acousto-optic medium, and the angle between the [010] axis of the lithium niobate crystal and the incident light is 0.5°±0.3°. The present invention adopts lithium niobate crystal as the acousto-optic medium, improves the acousto-optic figure of merit of the lithium niobate crystal, and also improves the ability of the acousto-optic device to withstand high-power lasers; at the same time, the present invention also plates an anti-reflection film on the light-transmitting surface of the acousto-optic medium to improve the utilization rate of light energy by the acousto-optic device. Overall, the present invention can better meet the modulation requirements of high speed and high threshold.

The invention relates to the technical field of laser control, and discloses a laser control method and device for an ultra-pulse thulium-doped fiber laser operation system, and the method comprises the steps: generating a PWM time-base waveform through an FPGA, and generating a reference duty ratio instruction based on a target pumping current value; the total response delay time of the acousto-optic modulator is calculated, the FPGA sends a trigger pulse to the acousto-optic modulator according to the total response delay time, the gated modulation laser is output to the optical fiber output end to obtain an analog voltage signal, and the analog voltage signal and the numerical value of the target power register are used for calculating a duty ratio correction increment; the duty ratio correction increment and the reference duty ratio instruction are updated to a duty ratio register of a PWM time base waveform, and multiple paths of pump cooperative driving waveforms are output. The technical problems of pump current response lag, acousto-optic modulator triggering jitter and optical power nonlinear saturation in an ultra-pulse thulium-doped fiber laser operation system are solved; and the laser pulse energy stability, the response speed and the long-term reliability are improved.

The invention relates to the technical field of additive manufacturing, in particular to a photocuring printing scattering suppression method and system based on acousto-optic modulation. According to the method, in the photocuring printing process, an acousto-optic modulation device is used for generating a focused ultrasonic field in a printing material, specific refractive index distribution is formed in the material based on the photoelastic effect, and therefore a refractive index regulation and control area used for restraining and guiding scattered light propagation is constructed in a local space; therefore, the scattering effect is suppressed, and the forming precision and the structural fidelity are improved. The system comprises a photocuring device, a light source, a printing platform and an acousto-optic modulation device used for achieving the method, the acousto-optic modulation device is composed of an ultrasonic transducer and an acoustic lens, and the acousto-optic modulation device forms a focusing sound field under external excitation and works in cooperation with the light source. The method is suitable for photocuring printing of various high-scattering light-sensitive composite materials, comprises material systems containing particles, cells or components with remarkable refractive index difference, and has good material adaptability.

The invention relates to the field of quantum sensing, and provides an SERF atom magnetometer based on pi pulse pumping detection and a magnetic field detection method. According to the method, 770nm pumping light and 795nm detection light are modulated into an alternating pulse sequence through an acousto-optic modulator, optical frequency shift interference is avoided by adopting a time division multiplexing technology, and pumping pulses are configured to have a pi rotation effect so as to enhance atomic spin polarization. The device comprises an alkali metal gas chamber with multiple layers of magnetic shielding, a graphene heat conduction non-magnetic heating system based on infrared laser, a time division control light path module and a synchronous signal processing unit. Electric heating is replaced by laser heating to eliminate magnetic noise, a pulse interval tau adjustable mechanism is utilized to balance sensitivity and measuring range, and common-mode noise is suppressed in combination with differential photoelectric detection and phase-locked amplification technologies. The alternating current stark effect caused by continuous illumination and magnetic field interference of traditional heating are overcome, the magnetic field measurement precision, the system stability and the signal-to-noise ratio are improved, and a high-precision weak magnetic field detection scheme is provided for biomedical detection and quantum navigation.

The invention discloses a wavelength division multiplexing phi-OTDR and BOTDR fusion demodulation method, system and device and a storage medium, and relates to the technical field of distributed optical fiber sensing, and the method comprises the steps: employing a double independent narrow linewidth laser to output continuous laser, enabling each path to be divided into two beams through a coupler, enabling one beam to be subjected to pulse modulation, and enabling the other beam to be used as local oscillation light; pulse light is modulated into frequency-shift pulse light through an acousto-optic modulator, and the frequency-shift pulse light is injected into a sensing optical fiber after being combined by an optical combiner. And the backscattered light is separated by the optical wave separator according to the wavelength. Rayleigh signals are subjected to coherent receiving and orthogonal demodulation to obtain light intensity; brillouin signal amplification, frequency mixing and the like are performed to extract frequency shift. In combination with light intensity and frequency shift, temperature strain is decoupled, and vibration information is demodulated; according to the invention, the measurement precision is improved, and the line potential risk can be found in time; efficient signal isolation and transmission and temperature strain decoupling measurement are achieved, and pipeline safety is guaranteed; the structure is simple and easy to expand, and long-distance, low-cost and high-precision monitoring and timely disaster early warning can be realized.

The invention provides a high-efficiency micro-ring acousto-optic modulator, which combines high sensitivity and sound wave regulation and control capability of a micro-ring resonator, adopts two pairs of optical waveguides and acoustic waveguides with grating couplers, realizes flexible control of sound wave and light wave propagation directions, can be configured to perform common or reverse propagation, and can be used for acoustic wave and light wave propagation. The method is suitable for exploring the time reversal symmetry and the optical nonreciprocity of the system. The device adopts the sapphire substrate, by virtue of high mechanical strength, high sound velocity and low acoustic loss, the sound wave mode quality and transmission stability are improved, and meanwhile, high-quality integration with silicon dioxide and lithium niobate films is ensured; the silicon substrate has remarkable advantages in the aspects of micro-nano processing, heat conductivity and electro-optical system compatibility, and large-scale manufacturing and system integration are facilitated. In addition, a chalcogenide waveguide with low optical loss is introduced into the device, so that the light field constraint and locality are enhanced, the overlapping and coupling strength of an acousto-optic mode is improved, and meanwhile, the interface scattering loss is reduced.

The invention discloses a distributed sound wave sensing device based on PDH frequency locking and a demodulation method. The distributed sound wave sensing device comprises a narrow linewidth laser, a first optical fiber coupler, a heterodyne phase sensitive optical time domain reflectometer and a frequency stabilization feedback module. The frequency stabilization feedback module comprises a frequency stabilization modulation and demodulation module, a reference cavity and a server; the frequency stabilization modulation and demodulation module comprises an electro-optical modulator or an acousto-optical modulator, a photoelectric detector, a multiplier and a low-pass filter; the first path of light enters a reference cavity for resonance after being modulated by an electro-optical modulator or an acousto-optical modulator, a resonance signal enters a photoelectric detector through cavity reflection, and a signal output by the photoelectric detector is subjected to signal demodulation by a multiplier and a low-pass filter and then is used as feedback to be input into a server for proportional-integral processing; the laser is fed back and output to a modulation interface of the narrow-linewidth laser, and frequency compensation is performed on the laser, so that the laser is locked on the reference cavity; according to the invention, through frequency stabilization and homologous modulation and demodulation, line width and phase drift of the laser can be suppressed at the same time.

In the field of ultrastable laser technology, tuning an ultrastable laser maintains its performance indicators without increasing additional lock noise and out-of-loop drift. [Solution] One acoustic-optic modulator and one electro-optic modulator are introduced separately, and the laser device, frequency shift unit, PDH frequency stabilization control unit, and ultra-stable cavity are integrated. [Effects] By changing the frequency of the acousto-optic modulator, high-precision tuning of the ultra-stable laser can be achieved. By changing the frequency of the electro-optic modulator, wide-range tuning of the ultra-stable laser can be achieved, enabling wide-range, high-precision, and dead-zone-free frequency tuning.

The invention provides a frequency modulation laser ranging and vibration measurement common-path design method, which belongs to the technical field of laser measurement and comprises a measurement light path, an auxiliary light path and a calibration light path. The measuring light path comprises a single-frequency laser and a tuning continuous wave laser, beam combination, modulation and beam splitting of measuring light beams are achieved through components such as a coupler, a circulator, an acoustic optical modulator, a wavelength division multiplexer and a collimating lens, and finally signals are received by a photoelectric detector. The auxiliary optical path adopts a Mach-Zehnder interferometer structure, and uses an optical fiber disc to generate an optical path difference for auxiliary measurement. The calibration light path accurately calibrates the laser frequency through an etalon and a photoelectric detector. The design effectively improves the integration level, stability and measurement precision of the system through a common-path structure, and is suitable for high-precision laser ranging application.

The application discloses a vortex light interference device and method for measuring three-dimensional vibration and sound field rotation characteristics, wherein a helium-neon laser emits laser light, the laser light passes through a half-wave plate and a first polarization beam splitter prism, and is divided into object light and reference light; the object light passes through a first spiral phase plate and becomes vortex object light, the vortex object light passes through a second polarization beam splitter prism, a quarter-wave plate, and a beam expander lens, and is irradiated on a test sample surface, reflected light of the sample surface passes through the beam expander lens, the quarter-wave plate, the second polarization beam splitter prism, a beam splitter prism and a focusing lens, and is irradiated on a photodetector; the reference light passes through an acousto-optic modulator to generate frequency modulation, passes through a mirror and a second spiral phase plate to become frequency-modulated vortex light, and the vortex light passes through a beam splitter prism and a focusing lens and is irradiated on the photodetector; a computer calculates and demodulates frequency-modulated signals of the photodetector and modulation signals of the acousto-optic modulator, and finally obtains three-dimensional vibration information and sound field rotation characteristics of the sample.

The present invention discloses a low-loss and low-power compact heterodyne acousto-optic modulation module. The 0th-order light output by the first fiber acousto-optic modulator is used as the incident light to connect to the output light position of the 1st-order diffracted light of the second fiber acousto-optic modulator; the 1st-order diffracted light output by the first fiber acousto-optic modulator is used as the incident light to connect to the output light position of the 0th-order light of the second fiber acousto-optic modulator; the incident light position of the second fiber acousto-optic modulator is used as the output light position to output the outgoing light; the two-stage fiber acousto-optic modulators adopt the same drive circuit and the radio frequency signals work alternately. The drive circuit of the present invention adopts a scheme of external clock input, homologous dual channels, adjustable dual-channel delay, and timing control. The present invention does not have a fiber coupler. By controlling the diffraction of the two AOMs relative to the trigger signal to adjust the relative delay between pulses, and controlling the turn-on time of the two AOMs to obtain two pulse signals with different frequencies, it has the advantages of low power consumption, small loss, and arbitrarily adjustable delay.

The invention discloses a device and a method for testing frequency domain characteristics of a high-speed optoelectronic device. The device comprises a laser, a sawtooth wave generator, a signal source, an acousto-optic modulator, an electro-optic intensity modulator, a low-frequency photoelectric detector, a frequency spectrograph and a computer. An electro-optic intensity modulator is driven through a sawtooth wave modulation technology, and frequency-shifted and non-frequency-shifted optical carriers and frequency-shifted and non-frequency-shifted radio frequency optical sidebands are synchronously generated in an optical path in combination with radio frequency signal modulation. And after the signal is subjected to beat frequency processing by the photoelectric detector, the power of the frequency shift signal in different working states is measured by the frequency spectrograph, so that the frequency domain characteristic parameters of the photoelectric device to be measured are obtained. The method is based on sawtooth wave modulation and an amplitude comparison method, frequency domain response characteristics of a single / dual-drive electro-optic intensity modulator, dual-parallel electro-optic intensity modulation and a photoelectric detector can be accurately represented, the test method is simple, and dependence on a high-frequency test instrument is effectively reduced.

The application provides a distributed optical fiber acoustic wave sensing system and a pattern recognition method. The application relates to the fields of optical fiber sensing and pattern recognition, and the system comprises the following steps: continuous coherent light emitted by a narrow-line-width laser is split into two paths by a beam splitting fiber coupler, one path is used as local reference light, and the other path is used as probe light; the probe light is modulated into optical pulses in an acousto-optic modulator driven by a waveform generator, and the optical pulses are injected into a measured sensing optical fiber through a fiber loop; Rayleigh backscattering light returned through the measured sensing optical fiber is mixed with the local reference light through the fiber loop, and the mixed light is decomposed into two orthogonal polarized light beams in a polarization beam splitter and is transmitted to a first balanced photodetector and a second balanced photodetector respectively to be converted into electrical signals; and the two orthogonal interference electrical signals are synchronously collected by a data acquisition card and are sent to a host computer for demodulation. The application provides a new distributed acoustic wave monitoring method with high reliability and high generalization ability, and has extremely high engineering popularization value.

The invention relates to the technical field of thermal interface material defect detection, in particular to a nondestructive detection method and system for thermal interface material application defects, and the system comprises an electric displacement table, heating laser, detection laser, a photoelectric detector, an acoustic optical modulator, a lock-in amplifier, an optical element and a data processing unit; the electric displacement table is used for fixing a sample and accurately controlling the position of the sample; the sample is of a silicon-thermal interface material-substrate sandwich structure; the upper-layer silicon wafer of the sample is plated with a metal film as a transduction layer; the heating laser is used for heating the sample; the acoustic optical modulator is used for modulating the heating laser, so that the heating laser heats the sample in a sine wave form; the detection laser is used for detecting sample temperature fluctuation; the photoelectric detector is used for collecting and detecting laser reflection signals; the lock-in amplifier is used for extracting and detecting laser phase and amplitude signals. According to the invention, non-destructive rapid detection of the defects of the thermal interface material in an application scene can be realized.

The invention discloses a coherent optical frequency signal regeneration amplification system based on optical fiber transmission. The coherent optical frequency signal regeneration amplification system comprises a local narrow linewidth laser which outputs narrow linewidth laser; the first optical fiber coupler couples the narrow linewidth laser to the first acoustic optical modulator and the second acoustic optical modulator respectively; the output of the first acousto-optic modulator and superior transmission light are jointly coupled into a photoelectric detector by a second optical fiber coupler to generate a beat frequency signal; the signal processing module samples the beat frequency signal after conditioning the beat frequency signal, performs phase discrimination on the sampled signal and the digital reference signal to generate an error signal, and generates a first feedback signal and a second feedback signal according to the error signal to be respectively used by the local narrow linewidth laser and the first acousto-optic modulator; performing real-time cycle slip detection on the error signal and repairing a phase abnormal point to generate a third feedback signal to be used by a second acousto-optic modulator; and the second acousto-optic modulator outputs amplified regenerated laser. According to the invention, high-precision optical frequency signal transmission can be realized in a complex and changeable optical fiber environment with large noise.

The application relates to a polarization holographic multiplexing display system and method based on an acousto-optic modulator, wherein a beam splitter is arranged in front of a spatial light modulator; a laser, a first linear polarizer and the beam splitter are sequentially arranged on an optical path of the laser; a first lens, a pinhole, a second lens and a first polarization grating are sequentially arranged on a reflection optical path of the beam splitter; four circularly polarized lights are arranged behind the first polarization grating; a reflecting mirror, an acousto-optic modulator, a third lens and an image sensor are sequentially arranged on an optical path of a first light beam; a second polarization grating, a second linear polarizer and an image sensor are sequentially arranged on optical paths of a second light beam, a third light beam and a fourth light beam. The application can obtain three kinds of reconstructed images with different effects at different reconstruction distances, and has a good application prospect in the fields of holographic display, holographic storage and the like.

The application relates to the technical field of adjusting devices, and provides an adjusting device and a laser drilling machine. The adjusting device comprises a supporting seat, a sliding seat and a first adjusting assembly. The supporting seat is provided with a first inclined surface. The sliding seat is provided with a second inclined surface which is in sliding fit with the first inclined surface. An adapter for connecting an acousto-optic modulator is arranged on the sliding seat. The first adjusting assembly is connected to the supporting seat. The first adjusting assembly is configured to drive the sliding seat to move along the inclined direction of the first inclined surface. The adjusting device provided by the application can meet the requirement of accurate adjustment of the acousto-optic modulator.

The application discloses a kind of adjustable distributed optical fiber sensing performance promotion device, sensing system and method, device includes: narrow linewidth laser, acoustooptic modulator, first signal generator and frequency shift ring;Narrow linewidth laser is configured to output narrow linewidth laser to acoustooptic modulator;First signal generator is configured to generate pulse function signal, function signal controls acoustooptic modulator, and single-frequency laser is modulated into pulsed light;Acoustooptic modulator is configured to modulate single-frequency laser into corresponding pulsed light in acoustooptic modulator according to the pulse function signal generated by first signal generator;Frequency shift ring is configured to multiple cyclic frequency shifts of pulsed light into it, and generate broadband multi-frequency light output.The device generates MHz-level pulsed light by acoustooptic modulator modulation, and generates GHz-level broadband multi-frequency light by multiple cyclic frequency shifts of frequency shift ring, which is applied to sensing system, and the response bandwidth of sensing system can be improved, and the flexibility of sensing test is improved.

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 relates to the technical field of optical fiber sensing, in particular to a rapid demodulation method based on improved space phase shift, which comprises the following steps: firstly, designing a space phase shift angle, then constructing a space phase shift matrix, and finally demodulating the amplitude or phase of a signal through a demodulation formula. According to the method, the intermediate frequency matrix is directly utilized to construct the orthogonal matrix, the orthogonal space phase shift angle is designed and introduced, the first space phase shift matrix and the second space phase shift matrix are accurately designed, the relationship among the space phase shift angle, the sampling frequency and the acousto-optic modulator frequency shift is fully utilized, the calculation efficiency of system demodulation is effectively improved, and the system demodulation accuracy is improved. And complex frequency mixing filtering operation and additional hardware equipment required by a traditional demodulation method are reduced, and the system demodulation cost is reduced.

The invention relates to the technical field of laser interference measurement, and discloses a very long baseline laser interference ground time delay simulation method, which comprises the following steps of: outputting a laser beam through a laser to form an interference signal through unequal arm interference, and measuring and acquiring real-time change data of laser frequency by using a phase meter; storing the data, performing multi-path delay processing, converting the data into a voltage signal through digital-to-analog conversion, and modulating the voltage signal back to a laser beam through an acousto-optic modulator; and finally, performing beam splitting and beam combining interference on the laser beams subjected to different delay modulation to obtain an interference signal simulating very long baseline time delay, and analyzing delay information by a phase meter. The device comprises a laser, an unequal arm interference assembly, a phase meter, a digital analog converter, an acoustic optical modulator group, a beam splitting and combining assembly and a detection assembly. The method does not need to depend on an ultra-long distance physical baseline, and precise simulation of very long baseline time delay is realized through real-time measurement of frequency noise, delay modulation and interference feedback.

The present invention is applicable to the field of pulsed laser technology and provides a pulsed laser modulation system. The system includes: a laser seed source for emitting a laser signal; a polarization-maintaining circulator having an incident end, a first emission end, and a second emission end, with the laser seed source and the incident end of the polarization-maintaining circulator being located on the same optical path; a fiber preamplifier and a laser pulse stretcher, with the first emission end, the fiber preamplifier, and the laser pulse stretcher being sequentially arranged on the same optical path; and an acousto-optic modulator and a fiber amplifier, with the second emission end, the acousto-optic modulator, and the fiber amplifier being sequentially arranged on the same optical path. The present invention proposes a design scheme for a pulsed laser modulation device that integrates stretching, preamplification, and frequency selection. By using this scheme, a low-repetition-rate pulsed laser output with a compact structure, good stability, and a high signal-to-noise ratio can be achieved.

An acousto-optic system may include a laser source, and an AOM coupled to the laser source and having an acousto-optic medium and transducer electrodes carried by the medium. The acousto-optic system may also include an interface board with a dielectric layer and signal contacts carried by the dielectric layer, and connections coupling respective signal contacts with respective transducer electrodes. Each connection may include a dielectric protrusion extending from the AOM, and an electrically conductive layer on the dielectric protrusion for coupling a respective transducer electrode to a respective signal contact.