413 results about "Acousto-optic modulator" patented technology

The invention discloses a signal-to-noise ratio improvement method based on a multi-core optical fiber dual-channel distributed acoustic sensing system, and the method comprises the steps: carrying out the light splitting of light emitted by a narrow linewidth laser through a first coupler C1, enabling one path of light to generate a pulse signal through an acoustic optical modulator (AOM), enabling the other path of light to pass through a second coupler C2, and enabling the other path of light to pass through a second coupler C1; the pulse light is divided into two beams of transmission light, the two beams of transmission light are injected into a connected sensing optical fiber through two groups of erbium-doped optical fiber amplifiers (EDFA), two groups of filters, two groups of circulators and a fan-in coupler Fan-in Coupler, and the pulse light is subjected to backward Rayleigh scattering in the sensing optical fiber; based on a dual-channel DAS system, a multi-core optical fiber is used as a sensing optical fiber, three cores and four cores of the multi-core optical fiber are connected in series to form two sensing channels, seven-core space division signals are multiplexed, the equivalent self-noise pressure suppression effect of the seven-core space division signals is analyzed, after noise correlation is removed through a time domain dislocation-frequency domain phase shift method, the signal-to-noise ratio gain can be increased to 8.65 dB, and the signal-to-noise ratio gain can be increased to 8.65 dB. And the detection capability of the system on low-frequency weak signals can be improved.

The invention discloses an equivalent self-noise pressure suppression method and device based on a multi-core optical fiber space division multiplexing signal, light emitted by a narrow linewidth laser is split through a first coupler C1, one path of light passes through an acousto-optic modulator AOM to generate a pulse signal, and then the pulse signal passes through a second coupler C2 to generate a pulse signal; the pulse light is divided into two beams of transmission light, the two beams of transmission light are injected into a connected sensing optical fiber through two groups of erbium-doped optical fiber amplifiers (EDFA), two groups of filters, two groups of circulators and a fan-in coupler Fan-in Coupler, and the pulse light is subjected to backward Rayleigh scattering in the sensing optical fiber; based on the dual-channel DAS system, the multi-core optical fiber serves as the sensing optical fiber, three cores and four cores of the multi-core optical fiber are connected in series to form two sensing channels, seven-core space division signals are multiplexed, the equivalent self-noise suppression effect of the seven-core space division signals is analyzed, and the detection capacity of the system for low-frequency weak signals can be improved.

The invention discloses a frequency discrimination curve calibration system, method and device. A frequency locking technology is adopted, the output laser frequency of the seed laser is stably locked on an absorption peak of the atom / molecule absorption cell, and the problem of frequency drift of the seed laser is effectively solved. Meanwhile, two acousto-optic modulators are used for implementing accurate out-of-cavity passive frequency modulation on the seed laser, and the laser frequency is moved to a preset zero-speed frequency point of an optical frequency discriminator and a linear working area edge frequency point from an atom / molecule absorption peak position. In the calibration process, the telescope vertically points to the zenith, and atmospheric echoes with zero Doppler frequency shift are provided as reference. At the moment, the optical frequency discriminator measures and records the transmittance of a preset zero-speed frequency point in the center of the linear working area and the transmittance of an edge frequency point, and a new frequency discrimination curve can be derived based on the linear hypothesis of the frequency discrimination curve.

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.

According to the optical fiber interference sensor and the application method thereof, an electro-optical frequency comb is introduced to screen out two comb lines to form a photon-assisted millimeter wave light source, interference is carried out in two frequency spectral regions subsequently, common phase fluctuation is counteracted based on inherent phase coherence, and the strict requirement for the line width index of a laser is avoided. Meanwhile, the two acoustic optical modulators connected in parallel are introduced into the reference arm and the interference arm for frequency shift, the problem of co-frequency crosstalk caused by residual zero-order diffraction of the acoustic optical modulators is solved, and the sensing precision is substantially improved.

The invention discloses an equivalent self-noise pressure suppression method based on a dual-channel distributed acoustic sensing system, and the method comprises the steps: carrying out the light splitting of light emitted by a narrow-linewidth laser through a first coupler C1, enabling one path of light to generate a pulse signal through an acoustic optical modulator (AOM), enabling the other path of light to pass through a second coupler C2, and enabling the other path of light to pass through a second coupler C1; the pulse light is divided into two beams of transmission light, the two beams of transmission light are injected into a connected sensing optical fiber through two groups of erbium-doped optical fiber amplifiers (EDFA), two groups of filters, two groups of circulators and a fan-in coupler Fan-in Coupler, and the pulse light is subjected to backward Rayleigh scattering in the sensing optical fiber; according to the invention, based on a dual-channel DAS system, two fiber cores of the multi-core optical fiber are used as sensing optical fibers, and the space division signals of the two cores are multiplexed, so that the performance that the equivalent self-noise pressure drop is 2.54 dB in the frequency band of 100-1000Hz is realized under the condition that the noise correlation coefficient of the dual-core signals is 0.11, and the detection capability of the system on low-frequency weak signals can be improved.

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.

The invention provides a pulse laser frequency control device and method, and belongs to the technical field of pulse fiber lasers. Comprising a frequency measurement module used for acquiring the frequency of a first external control signal; the frequency selection and frequency division module generates and outputs a seed frequency signal and a frequency division coefficient according to the frequency of the first external control signal obtained by the frequency measurement module; the frequency generation module is used for receiving the seed frequency signal output by the frequency selection and division module and outputting a seed frequency trigger signal; the pulse generation module is used for acquiring the seed frequency trigger signal output by the frequency generation module and providing a seed pulse signal for the seed driver, and the seed driver outputs pulse light according to the input seed pulse signal; the current control module is used for receiving a second external control signal and providing a current driving signal for each pump driver; and the RAM controller is used for receiving a third external control signal and the frequency division coefficient output by the frequency selection and frequency division module, and controlling the acousto-optic modulator to work.

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 rapid temperature measurement method and device based on micro-air-chamber double absorption spectrums, and belongs to the field of laser absorption spectrum sensing. The device comprises a light source module, a linear frequency sweep control module, a temperature measurement module and a signal acquisition and temperature calculation module. According to the invention, the scanning source, the optical fiber Mach-Zehnder interferometer and the feedback control circuit are utilized to ensure the optical frequency sweeping linearity, and two absorption spectral lines with known frequency difference and carrying temperature information are generated through the acousto-optic modulator. The method comprises the following steps: mapping an absorption spectrum from a time domain to a frequency domain on the basis that the time difference of the same absorption peak on two absorption spectrums with fixed frequency difference on a time domain corresponds to the driving frequency of an acoustic optical modulator, namely delta T = T1-T2 corresponds to the driving frequency f of the acoustic optical modulator, and then calculating by extracting parameters related to temperature on the absorption spectrum of the frequency domain to obtain the temperature of the air chamber. The invention can solve the problem of complexity of the traditional Doppler broadening temperature measurement system, and has the advantages of small measurement volume, low cost, high speed, high stability, strong adaptability and the like.

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 invention discloses a Rydberg atom microwave electric field sensing system and method based on coupling light modulation, and belongs to the technical field of microwave electric field sensing. In the system, a Rydberg atom preparation module excites alkali metal atoms to a Rydberg state; the radio frequency module provides a local oscillator signal for the Rydberg atom preparation module; the coupling light modulation module modulates the broadband pulse signal to the coupling light through an acousto-optic modulator so as to change the intensity of the coupling light entering the Rydberg atom preparation module; the signal receiving and processing module collects transmission light signals passing through the Rydberg atom preparation module, matched filtering processing is carried out, microwave electric field information is extracted, and the transmission light signals are generated by alkali metal atoms under the combined action of to-be-detected signals, detection light, local oscillation signals and coupling light with changed intensity. According to the method, the measurement sensitivity and the signal-to-noise ratio are improved, higher environmental adaptability is achieved, and stable measurement performance can be kept under complex conditions.

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 a Bragg light generation system and method suitable for a Bragg atom interferometer, and the system comprises a laser device which is used for generating first laser with the frequency on a preset atomic absorption peak frequency band; the optical circulator is used for transmitting the first laser to the cascade acousto-optic modulator and receiving two beams of third laser returned by the cascade acousto-optic modulator; the cascade acousto-optic modulator is used for diffracting the first laser into two beams of second laser with opposite propagation directions through Bragg diffraction of the two acousto-optic crystals; the optical assembly is used for carrying out secondary diffraction on the two beams of second laser and reflecting the two beams of second laser which are obtained through diffraction and are perpendicular to each other to the cascade acousto-optic modulator; and the output module is used for carrying out light splitting sampling on the two beams of third laser and modulating the sampled third laser into Bragg laser of a target frequency band. According to the invention, path separation of the two Bragg laser beams is reduced through quasi-common-path, so that phase noise is reduced, and measurement precision is improved.

The invention discloses a GHz pulse train generation device and method, and relates to the technical field of laser, and the device comprises a seed light source, a first acousto-optic modulator, a 50: 50 coupler, an optical fiber loop, and a third acousto-optic modulator. Wherein the fiber loop comprises a second acousto-optic modulator, a first chirp long-period fiber grating, a polarization-maintaining double-clad fiber and a second chirp long-period fiber grating. By using the first chirp long-period fiber grating, the polarization-maintaining double-clad fiber and the second chirp long-period fiber grating, the dispersion effect in a fiber loop can be compensated, and the conversion rate of the chirp long-period fiber grating is relatively high, so that the transmission loss in the fiber loop can be reduced; group delay ripples of the chirp long-period fiber bragg grating and the optical fiber high-order LP0m mode are very low, the shape and the width of pulses in a GHz pulse string on a time domain can be controlled, and finally, the optical fiber of the chirp long-period fiber bragg grating is a polarization-maintaining double-clad optical fiber, so that the nonlinear effect can be effectively inhibited.

The present invention relates to a FreeTrig-based pulse output apparatus for an ultrafast laser, and a FreeTrig-based pulse output control method for an ultrafast laser. An output end of an optical fiber beam splitter is connected to an optical input end of a main acousto-optic modulator, and the other output end thereof is connected to an input end of an optical fiber collimator; an optical output end of the main acousto-optic modulator is connected to an input end of an optical fiber beam combiner; a control input end of the main acousto-optic modulator is connected to an output end of a control module; an output end of the optical fiber collimator is connected to an optical input end of an on-board auxiliary acousto-optic modulator, an output end of the on-board auxiliary acousto-optic modulator is connected to the input end of the optical fiber collimator, and a control input end of the on-board auxiliary acousto-optic modulator is connected to the output end of the control module; the output end of the optical fiber collimator is connected to the other input end of the optical fiber beam combiner; an output end of the optical fiber beam combiner is connected to an input end of an optical amplifier; an output end of the optical amplifier is connected to an optical input end of a free-space acousto-optic modulator; and a control input end of the free-space acousto-optic modulator is connected to the output end of the control module.

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.

A cable discharge optical fiber detection sensor belongs to the technical field of optical fiber sensing and comprises a light source, a single-mode optical fiber, an acoustic optical modulator, an erbium-doped optical fiber amplifier, a beam splitter, a circulator, a beam combiner, a photodiode, a data processor and an optical fiber cable. The positive magnetostriction annular optical fiber and the negative magnetostriction annular optical fiber are arranged on the two sides of the high-voltage cable respectively, and the cable sheath is arranged outside the high-voltage cable. The technical scheme of the invention not only overcomes the limitation of the traditional discharge detection method, but also provides a novel sensor which is high in sensitivity, strong in anti-interference capability and easy to deploy in a distributed manner for the safety monitoring of the high-voltage cable, and has important engineering application value.

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 discloses a relay station for digitally locking an optical fiber link and monitoring phase noise in real time, which belongs to the technical field of relay stations for optical fiber optical frequency transmission and comprises a main control circuit, a link locking circuit and a laser locking circuit. The link locking circuit is bidirectionally connected with the main control circuit, the link locking circuit sends a link locking error signal to the main control circuit, and the main control circuit sends a link locking instruction to the link locking circuit; the laser locking circuit is bidirectionally connected with the main control circuit, the laser locking circuit sends a laser locking error signal to the main control circuit, and the main control circuit sends a laser locking instruction to the laser locking circuit; the link locking circuit comprises an optical frequency digital phase-locked loop; and the optical frequency digital phase-locked loop adopts a DDS (Direct Digital Synthesizer) to drive an acousto-optic modulator to adjust the frequency and the phase of an optical frequency signal. An optical frequency digital phase-locked loop is adopted to measure a phase noise power spectrum in real time, link locking can be achieved, and meanwhile whether the power spectrum of a locked signal reaches a theoretical noise suppression limit or not can be judged.

Embodiment of this application relate to a digital control method for laser power stabilization. In the embodiments of this application, based on conservation of optical power, that is, the sum of inner-loop optical power and outer-loop optical power is input optical power, a digital proportion integration differentiation (PID) control method combining optical loops and temperature compensation is adopted, which can optimize and adjust a PID control algorithm parameter in a large range in time, make up for the defect that an acousto-optic modulator (AOM) is sensitive to temperature, and meet stability requirements for high anti-interference ability, high precision and high stability of laser power. In addition, in the method, the target light intensity is set by means of a digital constant, thereby getting rid of the dependence on a high-performance voltage reference, reducing costs, and reducing sensitivity of a controller to an environmental parameter, thereby further enhancing a control ability.

The invention provides a monopulse heterodyne modulation system applied to an optical fiber hydrophone. A demodulation board outputs a linear frequency modulation signal to a tunable laser; the tunable laser modulates a laser signal through linear frequency modulation signal modulation, and outputs a continuous optical signal to the acousto-optic modulator; the demodulation board also outputs a path of periodic pulse signal to the acousto-optic modulator; wherein the sawtooth width of the linear frequency modulation signal is greater than the pulse width of the periodic pulse signal, and the sawtooth center of the linear frequency modulation signal is aligned with the pulse center of the periodic pulse signal; the acousto-optic modulator is used for modulating the continuous optical signal by adopting the periodic pulse signal and outputting a pulse optical signal; a pulse optical signal enters the optical fiber interferometer through the transmission optical fiber and is reflected by two arms of the optical fiber interferometer, then interference occurs at the output end, and an interference signal is obtained after photoelectric conversion. The scheme is high in vibration interference resistance and link interference resistance, and is favorable for realizing multi-time division multiplexing.

The invention relates to a wind measurement laser radar and a wind measurement method thereof. The wind measurement laser radar comprises a control device which sends out a first modulation signal and a second modulation signal; the light source module is used for emitting local oscillation light and signal light of continuous laser; the first acousto-optic modulator is used for receiving the signal light and carrying out frequency shift modulation and pulse modulation on the signal light based on the first modulation signal to obtain first modulation signal light; the second acousto-optic modulator is used for receiving the first modulation signal light and carrying out frequency shift modulation and pulse modulation on the first modulation signal light again based on the second modulation signal to obtain second modulation signal light; the telescope module receives the second modulation signal light, transmits the second modulation signal light to a to-be-measured target, and receives and outputs an echo signal reflected by the to-be-measured target; and the detection module is used for receiving the echo signal and the local oscillation light so as to generate a wind speed signal of the to-be-detected target. The wind measurement laser radar can greatly reduce or eliminate the trailing of the light waveform output by the combination of the two or more acousto-optic modulators.

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.