1363 results about "Circulator" patented technology

The embodiment of the invention provides a system for measuring a plane vector magnetic field, and the system comprises an optical path module which is provided with a laser, an optical fiber circulator, a long-pass optical filter and a photoelectric detector, a microwave module which is provided with a microwave source, a microwave amplifier and a microwave isolator, a signal processing module which is provided with a lock-in amplifier, and a magnetic generation device. The integration table device comprises a diamond NV color center sensor, a microwave antenna and two pairs of magnetic flux concentrators; during working, laser emitted by the laser device is output to the optical fiber circulator and then enters the diamond NV color center sensor so as to excite the diamond NV color center, and meanwhile, modulated microwaves which are output by the microwave source, are linearly amplified by the microwave amplifier and are transmitted again by the microwave isolator are used for regulating and controlling the electron spin state of the diamond NV color center so as to excite the diamond NV color center. The diamond NV color center outputs fluorescence with microwave regulation and control, and the fluorescence carries information of a plane vector magnetic field. The system can realize a high-isolation and high-sensitivity plane vector magnetic field measurement method.

The invention discloses a range gating anti-disturbance optical frequency domain reflection distributed measurement device and method. The device comprises a sweep frequency laser light source, a first optical coupler, a Mach-Zehnder modulator, a circulator, a detection optical fiber, a polarization controller, a second optical coupler, a balanced photoelectric detector and a data measurement unit. Wherein the Mach-Zehnder modulator is configured to perform BPSK modulation on the input probe light by using a pseudo-random spread spectrum coding technology. By means of the device and the method, the contradiction that long-distance measurement and fast frequency sweeping are difficult to achieve at the same time in a traditional OFDR is successfully solved.

The invention provides a frequency tripling circulator and electronic equipment, and the frequency tripling circulator comprises a grounding plate, a composite substrate located above the grounding plate, and an upper metal layer located on the composite substrate, the composite substrate comprises a ceramic substrate, and the surface of the ceramic substrate is provided with a through inner ferrite; the outer side of the inner ferrite is sequentially sleeved with a plurality of annular outer ferrites, and the saturation magnetization intensity of the inner ferrite and the saturation magnetization intensity of the outer ferrites are sequentially reduced from inside to outside; the upper metal layer comprises a central junction, the central junction is provided with three end points, each end point is connected with one port of the circulator through a metal transmission path, and the side edge of the central junction is provided with a plurality of SSPP grooves between two adjacent end points to form SSPPs branches. The scheme can have the characteristics of miniaturization and broadband, thereby satisfying more application scenes.

The invention provides a frequency-modulated continuous wave laser ranging device based on frequency shift double optical combs, which integrates frequency-modulated continuous wave and double optical comb technologies and comprises an FMCW light source, a beam splitter, a detection and reference light channel, a beam combiner, a photoelectric detector and a processing module. The FMCW light source outputs linear frequency sweeping laser which is divided into two paths through the beam splitter, and the detection light channel detects a target through the first optical comb generator and the circulator. The frequency fFS of the reference optical channel is increased through a frequency shifter, optical combs with different comb tooth intervals are generated by a second optical comb generator, and the fFS and the repetition frequency difference delta fR are in a non-integer multiple relation, so that interference is effectively avoided. After being combined by the beam combiner, the two paths of signals are converted into beat frequency signals by the photoelectric detector, and then time domain signals are spliced by the processing module by using coherence, so that the distance measurement precision is improved. According to the invention, the frequency shift double-optical comb technology improves the precision and anti-interference performance; an efficient data processing algorithm ensures rapid measurement and a wide range of application.

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 belongs to the field of microwave communication, and relates to a double-frequency microstrip circulator based on multi-layer material nesting, and the circulator comprises a substrate, a magnetic conductive sheet, a high dielectric ceramic, a high dielectric constant ferrite ring, a high magnetic saturation ferrite, a circuit layer, a ceramic sheet, and a permanent magnet. The magnetic conductive sheet is arranged at the bottom of the base body, the high-dielectric ceramic is arranged on the magnetic conductive sheet, the high-dielectric-constant ferrite ring is annularly embedded in the high-dielectric-constant ceramic, and the high-magnetic-saturation ferrite is embedded in the high-dielectric-constant ferrite ring. The circuit layer is arranged on the substrate consisting of the high dielectric ceramic, the high dielectric constant ferrite ring and the high magnetic saturation ferrite, the ceramic chip is arranged on the circuit layer, and the permanent magnet is arranged on the ceramic chip. The overall size is small, weight is light, and reliability is high; the working frequency range is wide, through different transformations, the system is not easily detected by enemies, the confidentiality is high, and the anti-interference capability is strong; the method can be widely applied to the fields of mobile communication, satellite communication, radar detection, electronic countermeasures and the like.

The invention discloses a multi-sideband chirp modulation DAS system and a working method thereof, and relates to the technical field of distributed sound wave sensing. The DAS system comprises a narrow linewidth laser, an optical fiber coupler, a phase modulator, an electro-optical modulator, an erbium-doped optical fiber amplifier, an optical fiber circulator, a dense wavelength division multiplexer, a photoelectric balance detector, a data acquisition card, an arbitrary waveform generator, a direct current source and the like. The phase modulator is used for modulating constant-amplitude multi-frequency continuous light, the frequency number of light waves is related to the harmonic number of a microwave modulation signal, the frequency interval is determined by the fundamental frequency of the microwave modulation signal, the continuous light frequency can be flexibly modulated by adjusting the microwave modulation signal, and the modulation bandwidth is large; detected beat frequency signals are compressed into single-frequency signals through pulses, phase information of the single-frequency signals is demodulated, vibration signals along the sensing optical fiber can be detected, the spatial resolution of the system depends on the chirp frequency sweeping range, and the spatial resolution is high.

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 high-resolution optical fiber integrated diamond color center sensor and a measuring method, the sensor comprises an optical fiber responsible for inputting exciting light and collecting fluorescence, the end face of the optical fiber is provided with a diamond color center, the diamond color center is excited by the output of the optical fiber, and a quartz capillary is arranged outside the optical fiber and the diamond color center. A microwave antenna is wound outside the quartz capillary tube, and a part of a bare wire of the microwave antenna is connected with the radio frequency line. The measuring method comprises the following steps: exciting a diamond color center; applying microwaves to the diamond color center; fluorescence generated by stimulated radiation of the NV color center is output by the optical fiber circulator and is input into the photoelectric detector through the filter; the upper computer controls the microwave generator to sweep frequency; the photoelectric detector performs photoelectric conversion, and the upper computer processes microwave frequency sweeping signals and electric signals. The magnetic field size and the temperature size of the sample to be measured in the micro space can be measured, and the device has the advantages of being high in spatial resolution, high in integration level, high in flexibility, high in controllability and the like.

The invention discloses a transmit-receive isolation system, and relates to the technical field of laser communication, a circulator of the transmit-receive isolation system comprises a first port, a second port and a third port, the first port is provided with a transmit-receive antenna, a light path from the first port to the second port is unidirectionally conducted, and a light path from the third port to the first port is unidirectionally conducted; the transceiving antenna is arranged at the first port; the signal processing module comprises a receiving end and a transmitting end; the first isolator is arranged between the second port and the receiving end, is in optical fiber connection with the second port and the receiving end, and is used for transmitting a remote optical signal in a one-way manner; the second isolator is arranged between the third port and the transmitting end, is in optical fiber connection with the third port and the transmitting end, and is used for transmitting a local optical signal in a one-way manner; according to the technical scheme of the invention, the invention provides the transmit-receive isolation system which is not limited by spatial light path arrangement.

The invention provides a composite ferrite circulator and electronic equipment, the composite ferrite circulator comprises a first bias magnetic circuit assembly, a ceramic gasket, a composite material substrate and a second bias magnetic circuit assembly which are sequentially arranged along a first direction, and one side, close to the ceramic gasket, of the composite material substrate is provided with a microstrip circuit; one side, close to the second bias magnetic circuit assembly, of the composite material substrate is provided with a grounding metal layer, the composite material substrate comprises a ceramic dielectric substrate, the surface of the ceramic dielectric substrate is provided with a cylindrical ferrite penetrating along the first direction, and the outer side of the cylindrical ferrite is sequentially sleeved with a plurality of circular ring ferrites; the saturation magnetization intensity of the cylindrical ferrite and the saturation magnetization intensity of the circular ferrite are sequentially reduced from inside to outside. According to the scheme, a higher relative bandwidth of the circulator can be realized, and the non-reciprocal transmission performance of the circulator is improved, so that the overall working performance of the electronic equipment is improved.

The invention relates to a phase-sensitive optical time domain reflectometer based on multi-frequency reference switching. Continuous laser generated by a continuous laser is divided into a local path and a detection path through an optical coupler; the local path is input to the polarization coherent receiving module, the detection path is incident to a light intensity modulator driven by the signal generation circuit module, and the light intensity modulator is converted into a multi-frequency pulse laser sequence with intensity modulation; the multi-frequency pulse laser sequence enters the sensing optical fiber to be measured through the optical circulator; generated Rayleigh backscattered light and local continuous laser are subjected to beat frequency coherent receiving in a polarization coherent receiving module through a circulator; and the signal acquisition circuit adopts a demodulation algorithm to compensate phase drift and sensitivity difference of detection pulse demodulation signals with different frequencies so as to realize dynamic strain sensing. Compared with the prior art, the phase drift and the sensitivity difference between the frequencies are extracted to realize the compensation of the interleaved signals, and the method does not depend on the fixed reference frequency, so that the robustness and the adaptability of the system in a complex environment are remarkably enhanced.

The invention discloses a double-comb non-cooperative target ranging system based on single photon detection, which is characterized in that an optical pulse output by a first optical frequency comb is divided into two paths of light through a first beam splitter, the first path of light is combined with one of two paths of light divided by a second optical frequency comb through a second beam splitter, and the combined light is transmitted to a first nonlinear frequency up-conversion module; a sum frequency light pulse in the wave band of 780 nm is generated and detected by a base avalanche diode photoelectric detector, and then a time-dependent single photon counter is triggered to start counting; the second path of light is output to a beam expanding collimator through the circulator and irradiates a target to be measured through spatial propagation, the beam expanding collimator collects diffuse reflection light and returns the diffuse reflection light to a third port of the circulator along the original path, and the diffuse reflection light and the other path of light split by the second optical frequency comb through the second beam splitter are combined and transmitted to a second nonlinear frequency up-conversion module; the up-conversion light after sum frequency conversion passes through the optical filter group and then is recorded by a stop end of the single photon counting module, multi-cycle accumulative statistics is carried out by the time correlation single photon counter, and finally a photon counting waveform is reconstructed and the flight time difference of the to-be-measured target is calculated by the computer.

The invention provides a sensing system fusing optical fiber vibration and acoustic emission, a monitoring method and a device, and relates to the technical field of optical fiber sensing. The device comprises a light source module, a sensing optical fiber, a detection module and a controller, the light source module is used for respectively emitting modulation pulse light for vibration monitoring and continuous wave laser for acoustic emission monitoring; the sensing optical fiber is arranged along a monitored structure or area, and at least one optical fiber acoustic emission sensing head is connected to the optical fiber in series. The detection module collects Rayleigh scattering light and beat frequency signals at all positions in the sensing optical fiber through a circulator and a coherent light receiver, and optical signals are converted into electric signals; wherein the electric signals comprise vibration electric signals and acoustic emission electric signals; the signal processing unit carries out phase demodulation and envelope analysis processing on the collected vibration electric signals and acoustic emission electric signals so as to obtain vibration waveforms and acoustic emission event space-time information along all points of the optical fiber. According to the invention, a monitoring task fusing vibration and acoustic emission can be accurately completed.

The present invention provides a transceiving coaxial phased array LiDAR chip and a control method therefor. The transceiving coaxial phased array LiDAR chip comprises: a laser emitting unit, a general beam splitter, a transceiving phased array, a balanced detector array and a signal processing and control unit; a phase modulator of a phased array unit in the transceiving phased array is separately connected to light-exit paths of the general beam splitter, and performs phase modulation on light output by the general beam splitter; after that, the light is divided into reference light and signal light, the signal light passing through a first port and a second port of a circulator and then being radiated by grating radiation antennas into a free space, and the reference light passing through a frequency shifter and then being input into a 90-degree optical mixer together with an echo optical signal returned by a third port of the circulator; then, balanced detectors receive output signals, convert same into electric signals and transmit same to the signal processing and control unit, so as to calculate three-dimensional depth and / or speed information of a target region. By means of a transceiving coaxial phased array LiDAR and a coherent detection means, the present invention achieves chip integration of a transmitting end and a detection end of the LiDAR, and has higher signal-to-noise ratio and integration degree compared with traditional LiDAR systems.

The invention discloses a single-frequency laser interference vibration measurement system and method based on optical fiber sensing. The system comprises a laser, a beam splitter, a circulator, a beam combiner, a coupler, a Faraday rotating mirror, a photoelectric detector and a data acquisition and processing module. Single-frequency laser emitted by the first laser is divided into two paths through the beam splitter, one path serves as signal light and irradiates the surface of a measured object after passing through the first circulator and the beam combiner, and reflected light returns through an original path; one path of interference signals is deflected by 90 degrees through a circulator II and a Faraday rotating mirror and then enters a photoelectric detector, the other path of interference signals directly enters the photoelectric detector, orthogonal I / Q signals are output, vibration displacement is extracted through a data acquisition and processing module by adopting a phase calculation method, and the vibration displacement is calculated through a phase calculation method. And the vibration speed is obtained through differential calculation. By optimizing the optical path design and introducing orthogonal signal processing, the system cost is reduced, and the measurement precision and the anti-interference capability are improved.

The invention relates to the technical field of microwave ferrite devices, and discloses a double-section microstrip circulator which comprises a magnetic conductive sheet, a ferrite gyromagnet and a resistor, the ferrite gyromagnet and the resistor are arranged on the upper surface of the magnetic conductive sheet, a circuit is additionally arranged on the upper surface of the ferrite gyromagnet, and the circuit is connected with a microstrip filter; the ceramic chip is arranged on the upper surface of the circuit, and samarium cobalt is additionally arranged at the top end of the ceramic chip, according to the two-section microstrip circulator, through the arrangement of a combined structure of the magnetic conductive sheet, the ferrite gyromagnet, the circuit, the microstrip filter, the ceramic chip, the samarium cobalt and the resistor, the isolation degree can be effectively improved, and the requirement of a system for high isolation is met; the microstrip filter in circuit connection can improve the second harmonic characteristic and improve the problem that the second harmonic of a conventional microstrip circulator is poor; the ferrite gyromagnet is used as a gyromagnet material, and is combined with a double-section circuit, so that the characteristic of low emission loss can be realized, and the circulator is small in size, light in weight and relatively high in reliability due to the integral structural design.

The invention discloses an interference elimination method for a same-time and same-frequency time synchronization system, which is suitable for a microwave time synchronization networking system and is characterized in that radio frequency domain self-interference cancellation is carried out before a signal received by a receiving end of a time synchronization networking node from an antenna enters a low noise amplifier; the introduced offset signal is obtained by coupling a part of a transmitting signal before the transmitting end enters an antenna from the transmitting end of the node, and correcting amplitude, time delay and phase through radio frequency reconstruction. The invention further discloses a same-time and same-frequency time synchronization system, the time synchronization networking node comprises a transmitting end, and a receiving end is connected to a receiving and transmitting antenna through a circulator; and a radio frequency self-interference suppression module is arranged between a first port of the circulator connected with the output of the transmitting end and a third port of the circulator connected with the input of the receiving end to sample a radio frequency signal output by the transmitting end and then realize radio frequency reconstruction, so as to generate an offset signal to be coupled to the input of the receiving end.

The invention provides a diaphragm type optical fiber liquid level sensing demodulation device and method based on a microwave photon technology, and the device comprises a broadband light source, a circulator, a diaphragm type optical fiber liquid level sensor, an erbium-doped optical fiber amplifier, a polarization controller, a DC power supply, a radio frequency source, an electro-optical modulator, a dispersion compensation optical fiber, a photoelectric detector and a power meter. The broadband light source is connected with a first port of the circulator, a second port of the circulator is connected with the diaphragm type optical fiber liquid level sensor, a third port of the circulator is connected with the erbium-doped optical fiber amplifier, the erbium-doped optical fiber amplifier is connected with the polarization controller, and the polarization controller is connected with the input end of the electrooptical modulator. The radio frequency source is connected with the modulation input of the electro-optical modulator, the direct current power supply is connected with the bias voltage input of the electro-optical modulator, the output of the electro-optical modulator is connected with the photoelectric detector through the dispersion compensation optical fiber, and the photoelectric detector is connected with the power meter, so that the measurement range is expanded while the sensing sensitivity and the resolution ratio are improved.

The invention relates to a phase-sensitive optical time domain reflectometer based on a parallel frequency division multiplexing sequence. Continuous laser is divided into a local path and a detection path through an optical coupler; the local path is input to the polarization coherent receiving module, the detection path is converted into a pulse laser sequence with intensity modulation through a light intensity modulator driven by a radio frequency signal provided by the signal generation circuit module, and the radio frequency signal is composed of two frequency division multiplexing sequences with difference; the pulse laser sequence enters the sensing link to be measured to generate Rayleigh backscattered light, and the Rayleigh backscattered light and local continuous laser are subjected to beat frequency coherent receiving through a circulator; and the signal acquisition circuit is used for sampling and analyzing the interference signal, and performing frequency domain comparison on an interleaving result of the two frequency division multiplexing pulse sequences to eliminate a harmonic frequency and retain a real strain signal frequency. Compared with the prior art, the non-harmonic strain signal measurement is realized, the high-frequency response performance and the high-precision strain measurement capability are excellent, and meanwhile, the long-distance coverage capability is also realized.

A distributed acoustic system (DAS) that may include two or more lasers that each transmit a continuous wave (CW) light, a pulser disposed after the two the two or more lasers and optically connected to each of the two or more lasers to receive the CW light from each of the two or more lasers and form a light pulse, and an optical amplifier, wherein the pulser is optically connected to the optical amplifier to receive the light pulse from the pulser as an input. The DAS may further include a splitter optically connected to the optical amplifier to optically split the light pulse into two or more light pulses for each output of the splitter a circulator optically connected to each output of the splitter, and a sensor fiber attached to each of the circulators as an output for each circulator.

An optical frequency domain reflectometer with environmental disturbance resistance and large strain measurement capability belongs to the field of distributed optical fiber sensing and comprises an opposite sweep frequency light frequency modulation continuous wave signal generation module, a light splitting device, a modulation device, a circulator, a polarization controller, an optical coupling device, a photoelectric conversion module and a data acquisition and processing module. An optical signal generated by an opposite sweep frequency light frequency modulation continuous wave signal generation module is divided into probe light and local oscillation light through a light splitting device, the probe light is modulated through a modulation device and sent to an optical fiber through a circulator, and a Rayleigh back scattering light signal generated by the optical fiber and the local oscillation light interfere in an optical coupling device to obtain interference light; the photoelectric conversion module mixes beat frequency signals of interference light, and the data acquisition and processing module analyzes and processes the beat frequency signals. According to the invention, the position information of the Rayleigh backscattering point is marked by using the modulated probe light, the Rayleigh scattering signal at the corresponding position is restored, crosstalk between channels is inhibited, and high-precision measurement in a large dynamic range and resistant to environmental disturbance is realized.

The invention discloses a rotor and stator axial clearance online measuring device and method based on optical carrier microwave interference. The measuring device comprises a broadband light source, a first polarization maintaining optical fiber, an electro-optical modulator, a second polarization maintaining optical fiber, an optical fiber circulator, a first single-mode optical fiber and a coated optical fiber probe which are connected in sequence, and the coated optical fiber probe directly faces the axial end face to be measured; a first port of the optical fiber circulator is connected with the second polarization maintaining optical fiber, a second port of the optical fiber circulator is connected with the first single-mode optical fiber, and a third port of the optical fiber circulator is sequentially connected with the second single-mode optical fiber, the photoelectric detector, the signal conditioning unit, the signal acquisition unit and the digital processing unit; the signal acquisition unit is connected with the micro-control unit, the micro-control unit is connected with the microwave frequency sweep signal generation unit, and the microwave frequency sweep signal generation unit is connected with the electro-optical modulator. According to the invention, non-contact on-line high-precision measurement of the axial clearance of the rotor and the stator of the aero-engine under the conditions of limited measurement space and complex signal leading-out path can be realized.

The present invention relates to the technical field of optical fiber sensing, and particularly relates to an optical time-domain reflectometer, and a method for eliminating interference fading. The optical time-domain reflectometer comprises: a laser device, a frequency-division multiplexing modulator, a circulator and a signal processing apparatus, wherein the frequency-division multiplexing modulator comprises a first modulator, a second modulator, a first attenuator and a second attenuator; the laser device is used for generating a coherent light source, and the coherent light source sequentially passes through the first modulator and the first attenuator, so as to obtain a first pulsed light signal; the coherent light source sequentially passes through the first modulator and the second modulator, so as to obtain a second pulsed light signal; and the coherent light source sequentially passes through the second attenuator and the second modulator, so as to obtain a third pulsed light signal. Therefore, by means of different combinations of the first modulator, the second modulator, the first attenuator and the second attenuator, multiple pulsed light signals can be outputted; and compared with the prior art, hardware costs are saved.

The invention discloses a frequency modulation matching microwave plasma generator, which is characterized in that a circulator is connected between a microwave source and a plasma resonant cavity, microwaves are input from a port 1 of the circulator, and are output to the plasma resonant cavity from a port 2, so that the reflected microwaves are output from a port 3. Meanwhile, a matched load and a power meter are connected to a port 3 of the circulator, microwaves output by the port 3 of the circulator are absorbed by the matched load, most returned microwaves are absorbed by the matched load, a small part of the microwaves are reflected back to the port 3, the microwaves input by the port 3 are output at a port 1, the microwave power borne by the microwave source is reduced, and the stability and the service life of the microwave source are improved. The control system adjusts the output frequency of the microwave source according to the measured power, so that the output frequency of the microwave source is improved, and the output impedance of the microwave source is matched with the working impedance of the plasma resonant cavity again, so that the back-and-forth reflection loss of microwaves is avoided; and the impedance matching adjustment speed is greatly improved.

The invention relates to the technical field of optical communication, in particular to a multi-channel shifting circulator. Comprising an optical fiber unit, a birefringent crystal, a polarization unit, a transmission or reflection unit, a polarizer and a reflection element, the optical fiber unit comprises at least four optical fibers, an optical signal can enter and reach the birefringent crystal along any optical fiber, and the birefringent crystal is used for splitting the optical signal into O light and E light; the transmission or reflection unit comprises a plurality of PBS films, and the number of the PBS films is the same as that of the optical fibers; the polarization unit changes the polarization states of the O light and the E light, so that the O light and the E light pass through the corresponding PBS films; the light enters the polarizer and is reflected back to the polarizer through the reflecting element, and the polarization states of the O light and the E light are changed, so that the O light and the E light are reflected to the adjacent PBS films on the corresponding PBS films; and the polarization unit can change the polarization state of the reflected light, so that the reflected light is emitted along the corresponding optical fiber after being combined by the birefringent crystal. Therefore, the method is suitable for a transmission application scene requiring more than three ports to realize optical signals.

The invention discloses a microwave tube type reaction device which comprises a reactor shell and a plurality of horizontal metal partition plates uniformly arranged in the reactor shell at intervals, the metal partition plates divide the internal space of the reactor shell into a plurality of same reaction cavities, a plurality of reaction tubes and metal tubes are arranged in the reactor shell in an array mode, and the metal tubes are arranged among the reaction tubes; waveguides are symmetrically arranged on the two opposite sides of each reaction cavity, the waveguides are symmetrically distributed on the two sides, the waveguides on the same side are connected with one waveguide slot antenna, the microwave generators are connected with the waveguide slot antennas through circulators, and all slots in the waveguide slot antennas are communicated with the corresponding reaction cavities through the waveguides. Uniform temperature distribution in the large-size microwave tubular reactor is realized by utilizing the waveguide slot antenna, the metal partition plate, the metal tube and the like, the amplification effect is reduced, and numerical amplification of the microwave tubular reactor is facilitated.

The invention relates to an arrangement for optical distance and / or speed measurement with a mode multiplexer in the coaxial transmission and reception path, wherein a different mode is used for transmission (i.e., light emission or the transmitter) than for the reception path. This eliminates the need for a circulator in the transmission path. The mode multiplexer thus assumes the function of branching the reception channel from the transmission channel and can be integrated as a PIC.

The invention discloses a power cable monitoring system and method based on single-core optical fiber multi-parameter sensing. The monitoring system comprises a laser, a first optical fiber coupler, an acousto-optic modulation unit, an optical fiber circulator, a distributed sensing optical fiber, a power cable, a wavelength division multiplexer, a second optical fiber coupler and a data acquisition monitoring unit. When the power cable to be detected is subjected to temperature change and vibration change, the temperature value of the power cable can be obtained by demodulating Raman scattering light data in backscattering light of the distributed sensing optical fiber, and Rayleigh scattering light in the backscattering light and local laser are subjected to interference frequency mixing to obtain a beat frequency signal; and the beat frequency signal is demodulated to obtain a vibration signal of the power cable. Based on the Raman scattering effect and the Rayleigh scattering effect, the temperature and vibration signals of the power cable can be detected at the same time only through one single-core optical fiber, and the method has the advantages of being high in signal-to-noise ratio, low in cost, easy and convenient to operate and the like.

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.