390 results about "Optical fiber coupler" patented technology

The invention provides an OFDR sensing system and method for rapidly positioning strain based on a time domain difference algorithm, and relates to the technical field of optical fiber sensing. The OFDR sensing system comprises a narrow linewidth tunable laser light source, a first optical fiber coupler, a main interferometer, an auxiliary interferometer and a data acquisition and signal processing module; laser emitted by the narrow linewidth tunable laser light source is divided into two paths through the first optical fiber coupler, one path of light enters the main interferometer, and the other path of light enters the auxiliary interferometer; the main interferometer and the auxiliary interferometer respectively output a main interferometer optical signal and an auxiliary interferometer optical signal to the data acquisition and signal processing module; the data acquisition and signal processing module is used for performing nonlinear compensation on the optical signal of the main interferometer by using the optical signal of the auxiliary interferometer, and performing cross-correlation operation on a reference optical signal of the main interferometer and a measurement optical signal of the main interferometer which are based on the strain-free state and the strain state of the sensing optical fiber and are subjected to nonlinear compensation; and obtaining the strain position and the strain value of the sensing optical fiber.

The invention discloses a Fabry-Perot interference type hydrogen detection device and method. The Fabry-Perot interference type hydrogen detection device comprises a broadband light source, a spectrograph, an optical fiber coupler, a sensing probe, a test gas chamber and a reference probe, the sensing probe and the reference probe are provided with sensor structures based on an optical fiber Fabry-Perot cavity, and the optical fiber coupler outputs input light emitted by the broadband light source to the sensing probe and the reference probe through a port A, a port B and a port C; light reflected by the optical fiber Fabry-Perot cavities of the sensing probe and the reference probe is output to a spectrograph through a D port, so that an interference spectrum is demodulated; hydrogen to be detected is mixed with air, then enters the test gas chamber through the gas flow rate controller, and is discharged from the outlet; the sensing probe adopts an anodic aluminum oxide / palladium film as a terminal reflector of a Fabry-Perot cavity, and an interference spectrum is detected through a spectrograph to obtain hydrogen concentration information in the environment; the reference probe adopts two single-mode optical fiber end faces to align in a sleeve and form an air Fabry-Perot cavity, and the reference probe only provides a stable reference spectrum to realize a vernier effect.

The invention relates to a self-coherence optical fiber interference device and method for simultaneously measuring morphology and thickness. The device comprises a light source module (1), a measurement light path (2), a compensation light path (3), a spectrograph (4), a mechanical motion module (6) and a data processing module (5), the measuring light path (2) comprises an optical fiber circulator (21), an optical fiber retroreflector (22) and an optical probe (23) and is used for realizing focusing measurement and enabling reflected light of the end face of the optical fiber retroreflector (22) and reflected light of a transparent object to be measured to return; reflected light of the end face of the optical fiber retroreflector (2) and reflected light of the transparent object to be measured form a measuring light beam, and the measuring light beam enters the compensation light path (3); the compensation light path (3) comprises an optical fiber splitter (31), an optical fiber delay line (32) and an optical fiber coupler (33), the measuring light beam is subjected to optical path compensation to generate a compensation light beam, and the compensation light beam and the measuring light beam are combined and input into the spectrograph (4) together.

The invention relates to the technical field of chip packaging, in particular to a photoelectric co-packaging underfill isolation packaging framework and process. According to the invention, the underfill glue blocking hole is additionally designed in the underfill glue diffusion area at the outer edge of the optical fiber slot hole on the adapter plate, and through the resistance effect (interface difference and liquid tension) of the underfill glue blocking hole on the flowing of the underfill glue, the glue overflow range is accurately controlled, and the underfill glue is prevented from covering the optical fiber coupler of the optical chip. By optimizing the underfill isolation design, efficient coupling of the optical chip and the optical fiber is ensured in the pollution direction of the underfill, meanwhile, the packaging gap between the photoelectric chips is reduced, and the packaging density and compactness are improved; the process tolerance, the product yield and the system performance of photoelectric packaging are remarkably improved, and the method is particularly suitable for the application fields of high-density and high-performance calculation and optical interconnection.

The invention discloses a vector flow velocity measuring device and method based on a bidirectional scanning spectral domain optical coherence tomography technology. Comprising a super light-emitting diode light source, an optical fiber coupler, a polarization controller, an interferometer comprising a sample arm and a reference arm, and a collimating lens, the collimating lens, the grating, the focusing lens group and the linear array camera are sequentially connected through a light path; the linear array camera, the computer and the two-dimensional galvanometer are sequentially connected through a line; according to the method, the fixed bias vector velocity is introduced by utilizing the bidirectional scanning technology, the dynamic light scattering optical coherence tomography method and the Doppler optical coherence tomography method are combined, decoupling of each parameter of the vector flow velocity is efficiently and accurately realized, and a quantitative index is provided for vector flow velocity analysis. The vector flow velocity measuring device based on the bidirectional scanning spectral domain optical coherence tomography technology is simple in system setting and low in cost, the time resolution is improved by about 2.5 times, and the measuring time is shorter.

The utility model relates to a control device for a microwave anechoic chamber test system. Comprising a shielding box which is a sealed cavity provided with a cover plate, and the shielding box is provided with a power supply socket, a data socket and an optical fiber coupler; a control circuit board, an AC-DC power supply module, a data optical fiber transceiver and other modules are installed in the shielding box. A plurality of motor control units, a power supply interface and a communication interface are integrated on the control circuit board, and a first output end of the AC-DC power supply module is connected with the control board and is used for supplying power to the control board; one end of the data optical fiber transceiver is electrically connected with the optical fiber coupler, and the other end is electrically connected with the communication interface for converting the signal into an optical signal and outputting the optical signal. The control circuit board is placed in the shielding box, so that the size of the rotary table or antenna tower equipment is reduced, and the electromagnetic interference risk of a motor and a darkroom environment is reduced; the control circuit board integrates the servo motor control unit and the stepping motor control unit for modular design, serves as an independent unit of the darkroom test system, and is high in universality.

The invention discloses a wind driven generator intelligent monitoring method and device based on an optical fiber sensor, and the method comprises the following steps: 1, optical fiber signal transmission and analysis: installing an optical fiber grating sensor in an area where a blade, a bolt and an air gap are located, and enabling the optical fiber grating sensor to be connected with an optical fiber grating signal analysis module through an optical fiber coupler, the analysis module sends an optical signal to the sensor and receives an optical signal reflected by the sensor; the fiber bragg grating signal analysis module demodulates the received optical signal, analyzes the change of optical wavelength, and extracts temperature, stress, vibration, deformation and air gap information of each monitoring point; through digital processing of sensing signals, the analysis module judges the state of blade, bolt and air gap information in real time and sends out an alarm signal according to a preset threshold value. 2, processing and outputting data; step 3, fault early warning and maintenance; according to the invention, the operation safety and efficiency of equipment can be improved.

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 application discloses a kind of EFPI optical fiber sensor multi-sensor multiplexing temperature-pressure demodulation system and method, including ASE broadband laser, optical circulator, EFPI optical fiber sensor, 2-way wavelength division multiplexer, N-way wavelength division multiplexer, N-way wavelength division demultiplexer, photoelectric detector, FBG, 1*2 optical fiber coupler, optical spectrometer, data processing system;The input port input of the optical circulator is connected with ASE broadband laser, the output port cir2 is connected with two cascaded FBGs, the output port cir3 is connected with EFPI optical fiber sensor, the input port of 2-way wavelength division multiplexer is connected with the output port cir4 of optical circulator, and the output port is connected with N-way wavelength division multiplexer;N-way wavelength division multiplexer is accessed via the input port of 1*2 optical fiber coupler, and outputs two-way signals, one-way is connected with N-way wavelength division demultiplexer via N-way photoelectric detector and data processing system, and the other way is connected with optical spectrometer;N channels are connected by cascaded FBG, and the cascade of N EFPI optical fiber sensors is realized.

The invention relates to the technical field of laser, in particular to a high-signal-to-noise-ratio modulation transfer spectrum frequency stabilization light path system. The system comprises a laser, an optical isolator, a first half-wave plate, a first polarization splitting prism, an optical fiber coupler, a second half-wave plate, a second polarization splitting prism, a first reflecting mirror, an electro-optical modulator, a second reflecting mirror and a third polarization splitting prism, wherein the first half-wave plate is used for adjusting the power of frequency stabilization light; the second half-wave plate is used for adjusting the power ratio of pump light to probe light; a first quarter-wave plate, a second quarter-wave plate, an atomic gas chamber and a photoelectric detector; after the output of the laser is isolated by the optical isolator, the first half-wave plate and the first polarization splitting prism are matched to adjust the frequency stabilization total beam power to about 5mW; the pump light is modulated by the electro-optical modulator, the probe light and the pump light reversely interact in the atomic gas chamber in an anti-phase circular polarization state, and the signal-to-noise ratio of a modulation transfer signal and the stability of a frequency stabilization system are remarkably improved.

The invention discloses an electrically-controlled variable optical attenuator based on a multistage wedge-shaped liquid crystal box and an attenuation control method, the attenuator comprises a laser, the laser provides an incident light signal, the divergent incident light signal is converted into a collimated parallel light beam through a collimator, the collimated parallel light beam is subjected to deflection modulation through a multistage wedge-shaped liquid crystal box module, and the modulated light beam is converted into a modulated light beam; the multi-channel liquid crystal controller is coupled to the output optical fiber through the optical fiber coupler, and generates and outputs driving voltage signals capable of being independently adjusted to the N-stage wedge-shaped liquid crystal box module, so that each wedge-shaped liquid crystal box in the multi-stage wedge-shaped liquid crystal box module is independently controlled; the control method comprises the steps of receiving a target instruction, querying a system-level relationship, distributing a deflection task, querying a device-level relationship, outputting a driving signal and performing closed-loop feedback correction. According to the invention, a large attenuation range is obtained, and at the same time, millisecond-level and even sub-millisecond-level rapid response is realized; the precision, the linearity and the usability of attenuation control are improved, and the control complexity is reduced.

The invention discloses an optical fiber laser phased array self-adaptive optical system based on an integrated optical chip. The optical fiber laser phased array self-adaptive optical system comprises a self-adaptive optical fiber coupler array, the integrated optical chip, an optical fiber splitter, a photoelectric detector, a control platform and a high-voltage amplifier. The integrated optical chip comprises an optical fiber coupling interface, a waveguide, a phase shifter, a Mach-Zehnder intensity modulator and the like. The adaptive optical fiber coupler array couples incident light to the optical fiber array, and corrects tilt aberration based on an optimization control algorithm to realize efficient adaptive coupling of spatial light to optical fibers; the sub-beams enter an integrated optical chip through an optical fiber coupling interface, phase and intensity modulation is performed on the sub-beams in the optical chip based on an optimization control algorithm, and co-phase synthesis output of the beams is realized; the output light is divided into two paths by the optical fiber splitter, one path is connected with the photoelectric detector for control, and the other path is connected with the application end. Based on light path reciprocity, the system has a transmitting or receiving and transmitting integrated function, and has important application prospects in the fields of space optical communication, laser energy transfer and the like.

The invention relates to the technical field of optical design, and discloses a double-beam differential measurement device and method for the polarization sensitivity of a metasurface grating, and the method comprises the steps: dividing a pre-generated light beam into a first light beam and a second light beam through an optical fiber coupler, carrying out the dynamic switching of the polarization state of the second light beam, and obtaining a second incident light beam, adjusting the first light beam based on the second incident light beam to obtain a first incident light beam; enabling the first incident light beam to pass through a first path without the metasurface grating, enabling the second incident light beam to pass through a second path comprising the metasurface grating, and obtaining a first output light beam and a second output light beam; performing time domain difference on the first output light beam and the second output light beam, and calculating to obtain a multi-polarization-state differential signal; correcting the multi-polarization-state differential signal through a preset differential correction mechanism to obtain a corrected differential signal; calculating the polarization sensitivity of the metasurface grating according to the corrected differential signal; according to the invention, the accuracy of the calculated polarization sensitivity of the metasurface grating can be improved.

The utility model relates to a system for measuring a PL spectrum of a C + L wave band wafer overall plane, and relates to the technical field of semiconductor lasers. Comprising a 980nm pump laser, an optical fiber coupler, a tapering optical fiber, a spectrograph, an electric control two-dimensional translation table, an objective table and a tapering optical fiber clamp. The objective table is used for bearing and fixing a tested wafer and realizing temperature control and heat dissipation of a test environment; the electric control two-dimensional translation stage is fixed with the objective table and drives the objective table to realize the overall displacement of the test wafer; the spectrograph is used for reading the measured light-emitting wavelength and intensity of the test wafer; and the optical fiber coupler is connected with the 980nm pump laser, the tapered optical fiber and the spectrograph, so that the whole optical path structure is connected in series, and the measurement and drawing of the overall plane PL spectrum can be realized. The testing device is simple and low in cost; the testing method is simple and easy to implement, high in accuracy and wide in application range.

The utility model provides a laser ablation device which comprises a first laser light source used for emitting treatment laser; the optical splitter is arranged at the output end of the first laser light source and is used for splitting the treatment laser into multiple paths of split laser; wherein the branch lasers are arranged in rows and columns; the optical modulator is arranged at the output end of the optical splitter and is used for performing independent power regulation and control on each branch laser; the optical fiber coupler is arranged at the output end of the optical modulator and is used for coupling the branch lasers into the optical fiber branches of the optical fiber array one by one; the optical fiber array is connected between the optical fiber coupler and the focusing micro-lens array, and each optical fiber branch corresponds to one focusing micro-lens of the focusing micro-lens array; and the focusing microlens array is used for focusing the split laser onto the diseased tissue in space through focusing microlenses for ablation treatment. The technical scheme can be used for ablation treatment of various irregular pathological tissues, and damage to surrounding healthy tissues is avoided.

The invention discloses a 2-micron-waveband adjustable all-fiber high-repetition-frequency pulse light source generator, belongs to the technical field of laser light source manufacturing, and aims to solve the problem that an existing 2-micron-waveband passive all-fiber mode-locked pulse laser light source is difficult to give consideration to fs-magnitude narrow pulse width and ultra-short-cavity-length high-fundamental-frequency repetition frequency output. The laser comprises a semiconductor laser pumping source, a wavelength division multiplexer, an extrusion type polarization controller I, a polarization-maintaining highly-doped gain fiber, an extrusion type polarization controller II, a long cone region tapering micro-nano fiber, a 2 * 2 fiber coupler and a fiber Faraday mirror. According to the invention, the long-cone micro-nanofiber is introduced into the cavity, and the long-cone micro-nanofiber has the characteristic of high nonlinear coefficient, so that the cavity length can be greatly shortened, enough nonlinear phase shift can be accumulated, and fs-magnitude ultrashort pulse can be output. The device is low in loss, stable in performance and easy to integrate with other optical fiber systems. The laser can be applied to the fields of optical communication, non-metallic material processing, laser medical treatment, intermediate infrared laser pumping sources and the like.

The invention relates to the technical field of power equipment, and discloses a high-voltage cable partial discharge detection device and an installation method, and the high-voltage cable partial discharge detection device comprises a housing, a quantum detection module, a radio frequency signal module, an optical signal module, a photoelectric conversion element, a signal analysis and processing module, and a control module. And the quantum detection module comprises a diamond which is arranged between the shell and the high-voltage cable and contains an NV color center. The radio-frequency signal module comprises a radio-frequency signal transmitting assembly, a radio-frequency signal receiving element and a radio-frequency signal transmission cable, and the radio-frequency signal receiving element is arranged on the shell. The optical signal module comprises a laser signal transmitting assembly, a first optical fiber, an optical fiber coupler and a condensing lens. The first optical fiber is connected with the photoelectric conversion element, and the photoelectric conversion element is electrically connected with the signal analyzing and processing module. According to the high-voltage cable partial discharge detection device, partial discharge detection of the high-voltage cable can be realized, and injury of high-voltage current to operators is avoided.

The invention relates to the technical field of measuring systems, in particular to an OCT (optical coherence tomography) measuring system based on reference arm light splitting, which comprises a light source, an optical fiber coupler, a reference arm switching device, a plurality of reference arms, a scanning detection mechanism, a detector and a spectrograph, light emitted by the light source passes through the optical fiber coupler, one path of light passes through the scanning part and is distributed to different depths such as the surface layer and the bottom of a to-be-detected object through the scanning detection mechanism, and the light returns to the optical fiber coupler along the original path after being reflected; the other path of light enters different reference arms through a reference arm switching device, the light of the reference arms enters an optical fiber coupler after being reflected, and the two paths of light enter a spectrograph after being interfered in the optical fiber coupler and are received by a detector; the multiple reference arms interfere with different depth reflected light information through the reference arm switching device; the measurement system is provided with an advanced signal processing host and an imaging system, can output images of the surface and the interested position of the object to be measured in real time, and improves the efficiency and accuracy of data processing.

The invention relates to the technical field of measurement, in particular to an automatic calibration device and method for a spectrograph. Comprising a light source, an optical isolator, an optical fiber coupler, a standard reference light source, an adjustable optical fiber attenuator, a first optical fiber collimator, a holographic frequency selection module, an electric reflector, a volume holographic grating, a second optical fiber collimator, a beam splitter, an optical interface unit, a spectrometer to be tested, a photoelectric detector, an electric reflector driver, an arc second level angle encoder, a control module and a communication module. A computer and an image display unit. The volume holographic grating is used for selecting a specific wavelength to measure the corresponding relation between the spectrograph pixel and the wavelength, monochromatic light can be continuously selected, and the theoretical resolution is consistent with the spectral resolution of the light source; automatic calibration of the spectrometer is realized by using an automatic calibration method, pixel-wavelength calibration data can be automatically generated and stored in a preset format, automatic calibration and data processing of spectral measurement software are facilitated, and pixel-level wavelength-pixel position registration is realized.

The utility model provides a penetration detection system and a laser welding system, the penetration detection system comprises a reference arm, a detection light source and a spectrometer, the detection light source is connected to a light splitting optical fiber coupler, and the light splitting optical fiber coupler splits detection laser into a first emergent light beam and a second emergent light beam; the first emergent light beam is transmitted to the laser welding galvanometer system through a second optical fiber and is reflected at a welding spot to form a first reflected light beam, and the first reflected light beam sequentially passes through the laser welding galvanometer system and the second optical fiber to return to the light splitting optical fiber coupler; the second emergent light beam is transmitted to the reference arm through the third optical fiber and then is reflected by the reference arm to form a second reflected light beam, and the second reflected light beam returns to the light splitting optical fiber coupler through the third optical fiber; and the first reflected light beam and the second reflected light beam are transmitted to the spectrograph through a fourth optical fiber after interfering at the light splitting optical fiber coupler. According to the utility model, the color difference between the detection laser and the welding laser can be effectively corrected, and the detection quality of OCT on penetration detection is improved.

The invention relates to a double-optical-comb laser and a laser spectrum measurement system, and the double-optical-comb laser comprises a pumping source which is used for generating pumping light. The optical fiber amplifier is connected with the output end of the pumping source, and the output end of the optical fiber amplifier is connected with the first optical fiber coupler. The first optical fiber coupler is connected with the first mode-locked laser cavity and the second mode-locked laser cavity. An output light path of the first mode-locked laser cavity is connected with the second optical fiber coupler, an output light path of the second mode-locked laser cavity is connected with the second optical fiber coupler, and the second optical fiber coupler is used for carrying out beam combination and frequency beating on the two paths of laser. The optical path delay line is used for adjusting the laser repetition frequency difference between the first mode-locked laser cavity and the second mode-locked laser cavity. The double-optical-comb laser not only overcomes the defects that an existing double-optical-comb system is complex, expensive and inconvenient to tune, but also has the advantages of being compact in structure, high in stability, high in output pulse energy and tunable in repetition frequency difference.

The invention relates to the technical field of optical measurement, and provides an electro-optical modulator parameter measurement device based on an optical fiber ring resonant cavity, which comprises an optical signal modulation system, an optical fiber ring resonant cavity system and a signal acquisition system which are sequentially connected through optical fibers, the optical signal modulation system comprises a to-be-measured electro-optical modulator which modulates an optical signal and outputs a modulated signal; the optical fiber ring resonant cavity system comprises an optical fiber coupler and a linear piezoelectric ceramic optical fiber stretcher; an annular optical fiber is formed based on an optical fiber coupler, and a plurality of reciprocating optical signal loops are formed in the annular optical fiber. The linear piezoelectric ceramic optical fiber stretcher is used for changing the length of the annular optical fiber; the signal acquisition system acquires signals and calculates parameters. Compared with the prior art, the method has the advantage that the resolution during measurement is improved.

The present invention discloses a device for generating an ultraviolet supercontinuum light source based on a subwavelength optical fiber, comprising: a pump light source, a first optical fiber coupler, and a subwavelength optical fiber sequentially arranged on the same optical path; the subwavelength optical fiber outputs an ultraviolet supercontinuum. The present invention also discloses a method for generating an ultraviolet supercontinuum light source based on a subwavelength optical fiber, comprising: emitting an optical pulse with a non-chirped sech-shaped waveform, a central wavelength of 400 nm, an initial pulse width ranging from 250 to 450 fs, and a pulse peak power of kilowatt level through a pump light source; the optical pulse is incident on the subwavelength optical fiber through the first optical fiber coupler for dispersion and nonlinear effects, and the subwavelength optical fiber outputs an ultraviolet supercontinuum. The present invention can generate an ultraviolet supercontinuum light source, solving the technical problem that it is difficult to extend the supercontinuum to the short wavelength band.

The invention relates to the technical field of optical fiber sensing, in particular to a distributed optical fiber sound wave sensing system based on an on-line interferometer, which is characterized in that a detection light signal sent by a distributed optical fiber sensing host passes through a relay amplifier and then is accessed into a circulator, and enters a downlink transmission optical fiber; a backward Rayleigh scattering signal generated by the detection optical signal in each relay section downlink transmission optical fiber is coherent with a local oscillation optical signal of the optical fiber interferometer to generate a disturbance monitoring signal of the relay section submarine optical cable; a disturbance monitoring signal is accessed to an optical fiber coupler of the relay section and enters an uplink relay amplifier of the uplink transmission optical fiber, and the disturbance monitoring signal is transmitted back to the optical fiber sensing host. And the working modes of the submarine repeaters are the same, so that each relay section can independently detect the optical fiber sound wave sensing signals. Therefore, the problem that the existing distributed optical fiber sound wave sensing technology cannot meet the requirement of relay submarine optical cable full-link detection is solved.

The invention discloses an ultrathin metal foil thickness measuring system and method based on Mach-Zehnder interference, and relates to the technical field of ultrathin metal thickness measuring methods. The system comprises a super-luminescent diode wide-spectrum light source SLD, the SLD emits a beam of white light, the white light is divided by a 50: 50 first optical fiber coupler into a light beam I and a light beam II with the same intensity, and the light beam I and the light beam II enter two Mach-Zehnder interference modules with the same structure respectively; the two Mach-Zehnder interference modules are symmetrically arranged along the upper side and the lower side of the sample to be tested, the output ends of the two Mach-Zehnder interference modules are connected with the input end of the second optical fiber coupler, and the output end of the second optical fiber coupler is connected with the input end of the spectrograph. The system and the method have the advantages of high real-time performance, high measurement precision, low cost and the like.

The invention discloses an optical time domain reflectometer based on ring structure modulation and a working method thereof, and relates to the technical field of optics. The optical time domain reflectometer comprises a laser, an optical fiber coupler, a semiconductor optical amplifier, an acoustic optical modulator, an optical isolator, a delay optical fiber, an erbium-doped optical fiber amplifier, a dense wavelength division multiplexer, a circulator, a Raman laser, piezoelectric ceramics, an arbitrary function generator, an arbitrary waveform generator, a polarization controller, a photoelectric balance detector, a data acquisition card, a computer and the like. Multi-frequency modulation is carried out based on an annular structure, the multi-frequency modulation range is only limited by the bandwidth of a detector and the sampling rate of an acquisition card, a pulse sequence is generated through modulation of the optical annular structure, dependence on the bandwidth performance of a microwave signal source and a modulator is reduced, and the bandwidth is improved; and by injecting the Raman light, the sensing distance is also increased, the equipment cost is effectively controlled, and meanwhile, a new scheme is provided for time sequence pulse sequence modulation.

The invention relates to an optical fiber coupler of a hollow-core anti-resonance optical fiber based on bidirectional tapering, belongs to the technical field of special optical fibers, designs a single-mode transition optical fiber with one side tapering and the other side reverse tapering, and solves the problem that mode fields are not matched when the single-mode optical fiber and the hollow-core anti-resonance optical fiber are coupled. According to the invention, coupling of the single-mode fiber and the hollow-core anti-resonance fiber can be realized; the optical fiber tapering and reverse tapering processes are adopted, the technological process is mature, and equipment is perfect; according to the invention, the transition optical fiber is used as a coupling medium to reduce local concentration of light intensity, thereby reducing the nonlinear effect and improving the optical power transmission capability.

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.

The invention relates to the technical field of optical fiber sensing, and provides a distributed optical fiber detection light source system based on pulse dense comb frequency modulation, and the system comprises a light source assembly which is used for generating detection light; the modulation device is connected with the light source assembly and forms a frequency shift ring cavity; the modulation device comprises a first optical fiber coupler, a delay optical fiber assembly, a double-parallel Mach-Zehnder modulator and an erbium-doped optical fiber assembly which are arranged in sequence; the modulation device is configured to modulate the frequency of the detection light in the frequency shift ring cavity; and the output optical fiber is connected with the output end of the first optical fiber coupler and is used for outputting the frequency-shifted detection light. The distributed optical fiber detection light source system based on the pulse dense comb frequency modulation is simple in structure, the speed of cyclic frequency conversion of the detection light in the frequency shift ring can be effectively reduced, then output of the detection light after frequency conversion is accelerated, and therefore the detection efficiency of the detection light used for detection is improved, and the detection time is shortened.

The present application provides an optical fiber-typed spectral confocal coherence tomography optical system and an application thereof. The system includes an optical fiber coupler, a broadband light source, a reference component, a sample component and a spectrometer. The reference component is connected to a first output end of the optical fiber coupler, for receiving a light source signal emitted by the optical fiber coupler and controllably forming the light source signal into an interference signal. The sample component is connected to a second output end of the optical fiber coupler, for receiving the light source signal emitted by the optical fiber coupler and forming a spectral confocal signal after the light source signal passes through a sample to be tested. The spectrometer is connected to a third output end of the optical fiber coupler.