120 results about "Fiber coupler" patented technology

The invention provides a detection method of an end face integrated reflection type SPR optical fiber biosensor manufactured based on a 2PP technology. An experiment system mainly comprises a single-mode optical fiber, an optical fiber coupler, an SPR probe, a tungsten lamp light source, a sample pool, a spectrum analyzer and a computer. The method is characterized in that a volcanic three-dimensional microstructure is directly constructed on the end face of a single-mode fiber through a 2PP technology, a metal film with the thickness of about 50nm is deposited on the inner wall of the volcanic three-dimensional microstructure, and a stable and efficient SPR excitation structure is formed; the structural parameters are subjected to FDTD simulation optimization design, and have the characteristics of high quality factor and high sensitivity. The sensor can be used for AFP detection, the sensitivity reaches 0.684 nm / (ng / mL) within the linear range of 0-10 ng / mL, the normal and risk early warning concentration interval of human serum AFP is covered, and the sensor has good biological suitability and early hepatocellular carcinoma screening capacity; in addition, the probe structure is small in size, detection can be completed only by a few microliters of liquid to be detected, and the probe is suitable for a microfluidic platform with an extremely low sample size or a clinical sampling scene. Compared with the prior art, the device has the advantages of high structural integration, high sensitivity, low sample consumption, convenience in manufacturing, stability, reliability and the like.

The invention provides an all-polarization-maintaining optical fiber mode-locked laser which comprises a linear cavity and an annular cavity. Wherein the annular cavity consists of a wavelength division multiplexer, an optical fiber coupler, a phase bias device, a gain optical fiber and a dispersion compensation optical fiber; the linear cavity is composed of an optical fiber coupler and an optical fiber reflector. As a function multiplexing device, an external electric field is applied to the phase bias device, so that the functions of continuous tuning of the phase difference in the positive direction and the negative direction in the annular cavity of the 9-shaped cavity mode-locked fiber laser and rapid phase tuning are realized, and the realization of a mode-locked state and a high-precision phase locking state is promoted. In addition, the composition structure of the resonant cavity can be simplified, and the repetition frequency and the system stability of the mode-locked laser can be improved. The technology for constructing the 9-shaped cavity mode-locked fiber laser by adopting the active phase bias device has originality in the field of ultrafast optics, and a better choice is provided for the all-polarization-maintaining fiber mode-locked laser.

The invention discloses a near-infrared wide-spectrum pulse light source generator, belongs to the technical field of laser light source manufacturing, and aims to solve the problems of complex system structure and high cost due to the fact that a supercontinuum laser generates supercontinuum through multi-stage power amplification in the prior art. The device is composed of a first semiconductor pump laser, a first wavelength division multiplexer, a first gain optical fiber, a first filter, a first dispersion compensation optical fiber, a first high-nonlinearity optical fiber, a first isolator, an optical fiber coupler, a second semiconductor pump laser, a second wavelength division multiplexer, a second gain optical fiber, a second filter, a second dispersion compensation optical fiber, a second high-nonlinearity optical fiber and a second isolator. According to the invention, the characteristic of high mode-locked pulse energy of the Mmyshev oscillator is utilized, multi-stage power amplification is not needed, and the super-continuum spectrum can be directly generated, so that the system structure is simplified, and the cost is reduced; the laser light source can be applied to multiple fields of laser sensing, photoelectric countermeasure, remote sensing detection, optical imaging and the like.

The invention discloses an OCT-based light splitting frequency doubling method and a measuring system, and relates to the technical field of optical coherence tomography, and the method comprises the following steps: a light beam emitted by a light source is divided into a first light path and a second light path through an optical fiber coupler, the first light path is transmitted to a collimating lens group through a scanning detection part optical fiber interface, and is transmitted to a second light path through a two-dimensional scanning part; scanning an object to be measured through a focusing lens; a second light path enters the reference arm part, sequentially passes through the polarization regulator and the reference arm collimating mirror group and then is reflected by the reference arm reflecting mirror group; the first light path and the second light path interfere with each other in the optical fiber coupler, and interference light enters the light splitting path detection component after being generated. Interference light is dynamically distributed to multiple detector channels through the light splitting element, efficient multiplexing of a light path is achieved, and different sampling rate and resolution requirements are flexibly met under the control of the main control card through three modes of light splitting, optical switch switching and scanning light splitting.

The application discloses a quantum random number generator based on feedback adjustment of a comparator threshold value and a random sequence generation method. The quantum random number generator comprises a superluminescent diode, a filter, an erbium-doped fiber amplifier, a fiber coupler with a coupling ratio of 50:50, an optical delay line, a first beam splitter and a second beam splitter with the same splitting ratio, a first optical power meter and a first photodetector connected with the first beam splitter, a second optical power meter and a second photodetector connected with the second beam splitter, a microcontroller connected with the first optical power meter and the second optical power meter, and a comparator connected with the microcontroller, the first photodetector and the second photodetector. The first photodetector and the second photodetector are connected with the comparator through a differential circuit. The application adjusts the threshold voltage to offset the influence of the output characteristics of a light source on the output random number.

A kind of multi-wavelength selection laser based on Ho doped crystal and its wavelength tuning method belong to the field of optoelectronic device manufacturing and optical engineering laser technology.To solve the function of multi-wavelength output of multi-wavelength selection laser, the pump source of 1940nm is connected with fiber coupler through fiber, the fiber coupler is arranged with fiber coupling lens group, polaroid, input plane mirror, Ho doped mixed crystal, output plane mirror and 1900nm narrow band filter in sequence along the light path;The Ho doped mixed crystal is composed of first square doped crystal, second square doped crystal, third square doped crystal and fourth square doped crystal, and the combination includes Ho: LLF crystal, Ho: YAP crystal and Ho: YLF crystal cut in different axial directions.The present application can efficiently realize tunable multi-wavelength output.By combining Ho doped crystals with different substrates, a laser is used to realize multi-wavelength output in a wide wavelength range.

Described herein are systems and techniques for providing photonic devices having efficient optical coupling between waveguides and optical fibers. The photonic devices comprise an edge coupler disposed within a cavity of a photonic integrated circuit (PIC) and a pluggable assembly removably coupled with the edge coupler. The PIC includes a spot size converter optically coupled to a waveguide to expand light received from the waveguide prior to exiting the PIC.

The invention relates to a weak pressure measurement method and system based on film reflection, the system comprises a light source, an optical fiber pressure probe, a signal acquisition module, a signal processing module and a signal display module, the optical fiber pressure probe comprises a film, a dual-optical fiber coupler and a sleeve, and the signal acquisition module comprises a photosensitive transistor and a driving circuit. And the signal processing module comprises a signal amplification circuit and a signal demodulation circuit. The method comprises the steps that when light beams emitted by the light source are projected to the surface of the film through the emission optical fiber, the film deforms under the action of external pressure, reflection light spot distribution and reflection angle change are caused, and signal modulation is achieved. The emergent optical fiber receives the reflected signal, the signal acquisition module acquires a light intensity signal of the emergent optical fiber and converts the light intensity signal into an electric signal, the signal processing module amplifies and processes the acquired information to realize signal demodulation, and the signal display module displays a processing result. The micro-pressure sensor has the advantages that micro-pressure measurement with low cost and excellent linearity is realized through a simple zero-point adjustment mechanism and a compact double-optical-fiber design.

The present application relates to the technical field of measurement, in particular to a kind of spectrometer automatic calibration device and method, comprising: light source, optical isolator, fiber coupler, standard reference light source, adjustable fiber attenuator, first fiber collimator, holographic frequency selection module, electric reflector, volume holographic grating, second fiber collimator, beam splitter, optical interface unit, to be measured spectrometer, photoelectric detector, electric reflector driver, angle-second level angle encoder, control module, communication module, computer and image display unit.The present application utilizes volume holographic grating to select the corresponding relationship between the pixel of spectrometer and wavelength, can continuously select monochromatic light, and the theoretical resolution is consistent with the spectral resolution of light source;Using automatic calibration method, the automatic calibration of spectrometer is realized, pixel-wavelength calibration data can be automatically generated and stored in preset format, which is convenient for automatic calibration and data processing of spectral measurement software, and realizes wavelength-pixel position registration at pixel level.

The application discloses a kind of rock mechanics test in the collection device of acoustic emission signal, including computer, measurement and control and signal processing equipment, distributed acoustic wave sensing equipment and collection probe: the collection probe is composed of single-mode optical fiber and probe skeleton, single-mode optical fiber is fixed around probe skeleton, when testing, collection probe is fixed on the surface of rock sample for testing;The measurement and control and signal processing equipment include: radio frequency amplifier, digital-to-analog conversion module, analog-to-digital conversion module, filter amplifier, field programmable logic gate array and CPU-GPU data processing module;The distributed acoustic sensing equipment includes narrow linewidth laser, fiber coupler, acoustooptic modulator, erbium-doped fiber amplifier, circulator, polarization diversity receiver, first balanced photodetector and second balanced photodetector;Collection signal band is wide, can be conveniently installed on any rock sample.Collecting main frequency is lower, collection probe is connected closely with rock sample, coupling is good, without additional smearing coupling agent.

The present application relates to a gas sensing system and method for graphene side-polished fiber optic bridges (FBGs). The system comprises: an amplified spontaneous emission (ASE) light source, a polarization controller, a fiber coupler, a spectrum analyzer, a real-time demodulation system, and at least one graphene side-polished FBG. The graphene side-polished FBG comprises a single-layer graphene and a side-polished FBG polished by a polishing device, wherein the single-layer graphene is used to tune the center wavelength of the side-polished FBG. The ASE light source is used to generate multi-path broadband light that sequentially passes through the polarization controller, the fiber coupler, and at least one graphene side-polished FBG. The polarization controller is used to tune the polarization state of the broadband light to tune the loss of the graphene side-polished FBG. The spectrum analyzer is used to receive the broadband light transmitted by the graphene side-polished FBG and analyze it to obtain an analysis result. The real-time demodulation system is used to obtain the concentrations of multiple gases to be measured based on the analysis result. This method can achieve efficient and accurate detection of multiple gases.

The invention provides a differential photoacoustic gas sensing system and method based on cross-correlation demodulation, and is suitable for the fields of trace gas monitoring, industrial process fine control and environment detection. The system comprises a gas excitation light source, a symmetrical double-probe gas sensor, an optical fiber circulator, a wide-spectrum light source, a 1 * 2 optical fiber coupler, two pieces of plain glass, a photoelectric detection array and a computer, acoustic wave signals excited by the photoacoustic effect generate difference superposition cavity length changes on the symmetrically-arranged double cantilever beams, and environment noise triggers cavity length responses which are counteracted in the same direction. The system adopts an optical cross-correlation demodulation algorithm to track peak displacement of a cross-correlation function in real time, dynamically demodulates cavity length change information, and inverts the gas concentration according to the information. According to the design scheme, effective photoacoustic signals are remarkably enhanced, meanwhile, effective suppression of environment vibration noise is achieved, and finally the trace gas detection system integrating the advantages of miniaturization, high sensitivity and low cost is constructed.

An interferometric quadrature detection system is disclosed that combines a reference or local oscillator signal with a sample or modulated signal in a fused fiber coupler having at least three outputs to generate phase-shifted signals. The phase-shifted signals are processed using either additional fused fiber couplers with balanced photoreceivers or single-ended photodetectors with subsequent analog subtraction to generate differential signals. The differential signals are used to reconstruct a complex-valued representation of the interferometric signal, enabling unambiguous recovery of amplitude and phase at or near the shot-noise limit. The disclosed methods and apparatus provide fiber-based alternatives to integrated optical hybrids and are applicable in optical coherence tomography, interferometric sensing, coherent optical communication systems and other applications.

A multi-core fiber coupler based on single-clad optical fibers (1), and a taper ratio design method therefor. Each single-clad optical fiber (1) comprises a fiber core (13), a cladding (12), and a coating layer (11), arranged in sequence from inside to outside. The multi-core fiber coupler based on single-clad optical fibers (1) comprises single-clad optical fibers (1) and a sleeve (2). Several single-clad optical fibers (1) are nested within the sleeve (2), and the total number of the single-clad optical fibers (1) is equal to the total number of fiber cores in a target multi-core optical fiber (3). One end of the sleeve (2) is tapered, and the other end is not tapered. A mode field diameter of each single-clad optical fiber (1) at the non-tapered end of the sleeve (2) matches a mode field diameter of a single fiber core of the target multi-core optical fiber (3). The single-clad optical fibers (1) and the multi-core fiber coupler have the advantages of low fabrication difficulty, low cost, and the capability of achieving low-loss connection with multi-core optical fibers and standard single-mode optical fibers.

The application relates to a mechanical hand control dispensing field, and discloses a feature recognition guide mechanical hand dispensing method, a computing device and a storage medium, the method comprises the following steps: recognizing a fiber coupler part feature according to a camera shooting tool plate image; when the part feature is identified as a taper area, a shearing pipe opening or a glass pipe opening, adjusting a light source according to a preset light adjustment condition corresponding to the taper area, the shearing pipe opening or the glass pipe opening, shooting a part image through the camera, and recognizing pixel coordinates of the taper area, the shearing pipe opening or the glass pipe opening according to the image; calculating dispensing coordinates of a mechanical hand according to the pixel coordinates of the taper area center, the pixel coordinates of the shearing pipe opening and the pixel coordinates of the glass pipe opening; and dispensing at the dispensing coordinate point through the mechanical hand control dispensing machine, the application adjusts the light source and the camera parameter matched with different part features of the coupler based on different part features, accurately recognizes the coordinates of the different part features, calculates the accurate dispensing coordinates of the mechanical hand, and improves the dispensing accuracy and the dispensing efficiency.

This invention discloses a fiber Bragg grating level sensor based on liquid pressure conversion, comprising a fiber Bragg grating demodulator, a 2×1 fiber coupler, a transmission fiber, and a sensing unit. The sensing unit consists of a strain-sensing fiber Bragg grating, a temperature-compensated fiber Bragg grating, a sealed cylinder, a support beam, a pressure block, a pressure tension frame, a sealing membrane, and a stop. The pressure block and the pressure tension frame convert liquid level changes into longitudinal displacement changes, causing axial strain in the strain-sensing fiber Bragg grating. This results in a drift in the center wavelength of the strain-sensing fiber Bragg grating, and the liquid level height of the container is measured by monitoring this wavelength change. This invention eliminates the influence of temperature on the liquid level measurement results through a temperature-compensated fiber Bragg grating, offering advantages such as a large measurement range, good practicality, simple structure, low cost, good stability, high sensitivity, and safety and reliability, meeting the needs of measuring liquid levels in large storage tanks and other applications.

The application relates to a fast demodulation system and method for a large-scale microcavity array on a chip, and the system comprises a frequency-sweeping laser, a first fiber coupler, a microcavity array transmission signal arm, an auxiliary interference reference arm, a same-frequency trigger arm and a signal processing device. The first fiber coupler is used for dividing a light source into a first light source and a second light source. The microcavity array transmission signal arm is used for receiving the first light source of the frequency-sweeping laser, and the first light source enters a large-array microcavity sensor device after polarization processing, and is converted into an electric signal after receiving the disturbance of an external sensing signal. The auxiliary interference reference arm is used for receiving the second light source of the frequency-sweeping laser, and two beams of coherent light with opposite phases are obtained after processing the second light source, and then the coherent light is converted into an electric signal. The same-frequency trigger arm is used for transmitting a same-frequency trigger signal emitted by the frequency-sweeping laser. The signal processing device is used for signal acquisition and processing. The application effectively suppresses the frequency-axis distortion and spectral line broadening caused by the frequency-sweeping nonlinearity of the laser, and can be applied to the accurate demodulation of a large-scale, high-Q microcavity sensing array.

The application relates to an all-fiber variable carrier laser sound field measuring device and a variable carrier modulation method, and relates to the technical field of laser application. The device comprises a main laser, a third fiber coupler, a fiber attenuator, a second fiber coupler, a balanced photoelectric detector, a signal acquisition card and an industrial computer; the third fiber coupler is further connected with an optical phase-locked loop; the optical phase-locked loop comprises the following components connected in sequence: a first fiber coupler, a phase detector, a signal amplifier, a frequency mixer, a voltage-controlled oscillator and a slave laser; wherein the frequency mixer is further connected with a local oscillator. The all-fiber laser coherent vibration measuring light path is adopted as the light path structure of the spatial sound field measuring system, can be disassembled and simply installed, and all the light paths are transmitted through optical fibers, so that the influence of ambient light can be avoided. The fiber attenuator in the local light path can adjust the attenuation coefficient in real time according to factors such as a detection distance and a detection angle, and the matching efficiency of the local light and the signal light is greatly improved.

The application relates to the technical field of optical communication, in particular to a three-dimensional waveguide chip, a preparation method thereof and a single-multiple core optical fiber coupler. The three-dimensional waveguide chip comprises a plurality of optical waveguides with equal diameters, an integrated fiber core bundle, a first end of the fiber core bundle is composed of linear arrangement of the optical waveguides, and a second end of the fiber core bundle is composed of circumferential arrangement of the optical waveguides or composed of central and circumferential arrangement; a three-dimensional coordinate system is established with the center of the fiber core bundle at the first end as an origin, an extension direction of the first end to the second end as an x-axis, a linear arrangement direction of the optical waveguides as a z-axis, and a direction perpendicular to the x-axis and the z-axis as a y-axis; the coordinates of the optical waveguides satisfy the following formula: wherein L is a distance between the first end and the second end, a is a y value of the center of the optical waveguide at the second end, b is a difference between a z value of the optical waveguide at the first end and a z value of the optical waveguide at the second end, and c is the z value of the optical waveguide at the first end.

The application relates to a refractive index micro-ring sensor based on a multi-core fiber taper and a measuring method thereof. The refractive index micro-ring sensor based on the multi-core fiber taper mainly comprises a light source, a single-core fiber, a first multi-core fiber coupler, a multi-core fiber taper, a second multi-core fiber coupler and a spectrometer; the middle part of the multi-core fiber taper is smaller than the two ends, so that a fiber taper area is formed in the middle part of the multi-core fiber, and a micro-ring is formed around the waist part of the fiber taper area; wherein: the output end of the light source is connected with one end of the single-core fiber; the other end of the single-core fiber is connected with one fan-in end of the first multi-core fiber coupler; the fan-out end of the first multi-core fiber coupler is connected with one end of the multi-core fiber; the other end of the multi-core fiber is connected with the fan-out end of the second multi-core fiber coupler; and one fan-in end of the second multi-core fiber coupler is connected with the spectrometer. Compared with the existing fiber refractive index sensor, the application has higher integration and improved sensitivity.

The invention relates to a multi-component gas sensing system based on a D-type optical fiber array. The system is characterized in that a femtosecond pulse mode-locked laser emits a femtosecond pulse sequence, the femtosecond pulse sequence is subjected to beam splitting processing through a first optical fiber coupler, and a first femtosecond pulse sequence and a second femtosecond pulse sequence are output; the third optical fiber coupler is used for carrying out beam splitting processing on the second femtosecond pulse sequence and outputting each path of femtosecond pulse sequence to pass through a corresponding optical fiber filter, a polarization controller, an electric delay line and a functionalized D-type optical fiber; the fourth optical fiber coupler is used for combining all the received femtosecond pulse sequences and outputting a sixth femtosecond pulse sequence; the second optical fiber coupler is used for combining all the received femtosecond pulse sequences and outputting a seventh femtosecond pulse sequence to the computer through the dispersion element, the front optical fiber amplifier, the optical fiber attenuator, the photoelectric detector and the A / D acquisition equipment, so that a multi-component gas detection result is obtained. And high sensitivity, high selectivity and rapid detection of multi-component gas detection can be realized.

The application relates to a liquid drop spraying device for an inertial particle dynamics experiment of an online cabinet of a space station, which comprises a fiber coupler, a spray head and a support, the fiber coupler and the spray head are both installed on the support, a light path channel and a liquid path channel are vertically arranged and cross arranged in the support, the spray head is coaxially installed at one end of the liquid path channel and communicates with the liquid path channel, and the other end of the liquid path channel is in an open structure; the fiber coupler is coaxially installed at one end of the light path channel and communicates with the light path channel, the intersection point of the central axis of the light path channel and the central axis of the liquid path channel is a light-liquid intersection point, and the liquid spraying end of the spray head is located above the light-liquid intersection point; the support comprises a support surface and an assembly surface, the spray head is installed on the support surface side of the support through a clamping assembly, the assembly surface of the support is used for assembling with a turbulent flow generating device, and the support surface and the assembly surface are arranged in parallel opposition or at an acute angle.

The application provides a self-calibration high-intensity optical fiber hydrophone based on an end face reflection principle and relates to the technical field of hydrophones.The application comprises the following steps: a laser light source emits a first laser beam, a fiber optical isolator inhibits reflection and outputs a second laser beam, a fiber adjustable optical attenuator adjusts incident power and outputs a third laser beam, a 1x2 fiber coupler divides the third laser beam into a fourth laser beam and a fifth laser beam, a first photoelectric detector monitors power, a fiber circulator transmits the fifth laser beam to a fiber sensing module, generates reflected light and transmits the reflected light to a second photoelectric detector, and the second photoelectric detector converts the reflected light into a voltage signal, a data acquisition card acquires the signal, a signal demodulation processing unit calculates sound pressure sensitivity according to a mapping relationship formula of the voltage signal and the sound pressure, and a standard voltage module provides a standard voltage for the data acquisition card.The application solves the problems that a high-intensity hydrophone cannot be reused and cannot be self-calibrated after being damaged in the prior art.

The invention provides an optical fiber hydrophone based on frequency domain multi-wavelength interference and a working method thereof. The device comprises a structure and an optical path part, in the structure part, a cylindrical measuring optical fiber (the cylindrical measuring optical fiber and a hollow cylindrical packaging body made of polyurethane sound transmission rubber form an integrated structure) for increasing the number of winding turns is packaged in the hollow cylindrical packaging body, and a reference optical fiber is wound outside a rigid supporting column; the light path part comprises a sweep frequency laser, an optical fiber coupler and other components, laser is transmitted to two optical fibers after being split by the coupler and is transmitted back and interfered after being collimated and focused by a convex lens and reflected by a reflector, and an interference signal is transmitted to a computer for data processing after being detected by a photoelectric detector. The device can detect weak low-frequency underwater acoustic signals.

The application discloses a kind of based on single-balanced detector's multiple contrast Jones matrix OCT imaging system, belong to optical imaging technical field.Sweeping laser light is divided into two beams by 1*2 broadband fiber coupler, one enters sample arm polarization delay module, generates two orthogonal sample lights of equal power, optical path difference is ξ, detects biological tissue, and sample returns the backscattering light transmission to 50 / 50 broadband fiber coupler by three-port fiber ring;With another into reference arm polarization delay module, generated two orthogonal reference lights of equal power, optical path difference is 2ξ, after interference, it is collected by a balanced detector.High-speed data acquisition card directly processes interference signal to realize real-time imaging;Another channel acquires k-clock signal, improves the detection accuracy of system by calculating correlation to system phase compensation.The application is suitable for medical fields and the like, to simplify system structure, reduce cost, save data processing time.

The application discloses a kind of based on the principle of OFDR's double-pulse long-distance distributed vibration detection device, including narrow linewidth laser light source and to-be-measured interferometer, and the application also includes auxiliary interferometer and phase noise demodulation and elimination mechanism, narrow linewidth laser light source includes NLL laser and first fiber coupler, the first output channel and the second output channel of first fiber coupler are connected with to-be-measured interferometer and auxiliary interferometer respectively, and to-be-measured interferometer and auxiliary interferometer are connected with phase noise demodulation and elimination mechanism.The application uses the above structure based on the principle of OFDR's double-pulse long-distance distributed vibration detection device, utilizes two homologous pulses to carry out Rayleigh scattering detection, mixes with auxiliary interferometer, realizes the elimination of phase noise, breaks through the limit of coherence length to range, realizes long range, frequency response high vibration signal detection, and only needs to mix in optical path twice, demodulation algorithm is simple, and phase correction speed is fast.

The application discloses a multi-edge-band chirp modulation DAS system and a working method thereof, and relates to the technical field of distributed acoustic sensing. The DAS system comprises a narrow-line-width laser, a fiber coupler, a phase modulator, an electro-optical modulator, an erbium-doped fiber amplifier, a fiber ring, a dense wavelength division multiplexer, an optical-electricity balanced detector, a data acquisition card, an arbitrary waveform generator and a direct current source. The application modulates continuous light with equal amplitude and multiple frequencies by using the phase modulator. The frequency number of the light wave is related to the harmonic number of the microwave modulation signal, and the frequency interval is determined by the base 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. The beat frequency signal detected is compressed into a single frequency signal, and then the phase information is demodulated, so that the vibration signal along the sensing fiber can be detected, and the spatial resolution of the system depends on the chirp sweep range, and the spatial resolution is high.

The present invention discloses an integrated system for optical fiber sensing and communication through sharing co-frequency resources. Specifically, the system consists of two parts: optical path detection and circuit demodulation. The entire system consists of a continuous wave laser, a fiber coupler, a polarization controller, a mach-zehnder modulator, an arbitrary waveform generator, an erbium-doped fiber amplifier, an optical filter, an optical fiber annular, an optical fiber, a photodetector, a data acquisition device, a balance detector and a data acquisition card. A transmission optical signal and a sensing detection light are generated by the same laser, transmission performance and sensing performance of the system are changed by adjusting modulation power of a transmission signal, the transmission signal is obtained by using direct detection at far-end, a sensing signal is obtained by using heterodyne coherent detection at local-end. The present invention provides a simple, compact and high-efficiency integrated system for co-frequency sharing optical fiber sensing and communication, to solve the deficiencies of the existing integrated system in practical applications.

A kind of vehicle-mounted ranging device and method, belong to distance detection technical field, device is by short coherence broadband light source, fiber coupler, wavelength division multiplexer, beam expander, optical splitter, lens, filter, area array camera and vehicle-mounted computer etc.; by vehicle-mounted computer real-time comparison two cameras image difference and the size of set threshold value, when vehicle-mounted computer determines that image difference is greater than threshold value, then it is explained that there is obstacle at the distance L in front of vehicle, vehicle-mounted computer issues alarm signal at this time.The present application adopts two light sources and two cameras, imaging twice in the same time, by the two images obtained are subtracted, eliminate interference fluctuation;The present application uses short coherence light interference technology, improves signal-to-noise ratio, can detect weak reflection signal;The present application selects broadband light source, longitudinal resolution is high, guarantees measurement accuracy while saves extra timing circuit;The present application uses area array camera to collect image, speed is fast, the number of imaging dot matrix is large, and lateral resolution is high.

The application provides a tunable laser fiber grating demodulator with high demodulation speed and a demodulation method, to solve the technical problems of complex calibration trigger algorithm, long time consumption, low sensing precision and slow demodulation speed in the prior art. The demodulator comprises a data acquisition and processing unit, a computer, a frequency sweeping laser unit connected in sequence, and a first fiber coupler, an HCN gas absorption chamber, a second fiber coupler, two second photoelectric converters, a fiber splitter, N fiber loopers, N-way fiber grating sensors and N first photoelectric converters. The inlet end of the HCN gas absorption chamber is connected with the output end of the first fiber coupler, to absorb P fixed wavelength lights output by the first fiber coupler and output wavelength absorption lines. The outlet end is connected with the two second photoelectric converters through the second fiber coupler. The two second photoelectric converters are both used for converting the wavelength absorption lines into pulse signals, and are used as trigger signals and calibration signals respectively.