970 results about "Single-mode optical fiber" patented technology

The invention discloses an optical fiber Fabry-Perot sensor for detecting C4F7N gas and decomposition products thereof, belongs to the technical field of C4F7N gas detection, and solves the problem of how to improve the sensitivity of the optical fiber Fabry-Perot sensor for detecting the C4F7N gas and the decomposition products thereof. According to the optical fiber Fabry-Perot sensor for detecting the C4F7N gas and the decomposition products thereof, the Fabry-Perot cavity is formed by the interval between the end face of the single-mode optical fiber and the surface of the groove, emergent light of the single-mode optical fiber is reflected by the surface of the groove, the reflected light is converged by the groove, the loss of the reflected light is reduced, and the detection accuracy of the C4F7N gas and the decomposition products thereof is improved. Gold is uniformly sputtered on one surface of the groove of the sensing diaphragm device layer to form a layer of reflecting film, so that the reflectivity is further improved, reflected light is efficiently coupled into the single-mode optical fiber, the contrast ratio of a light interference peak is improved, and the detection sensitivity of the sensor is further improved; the sensor is simple in structure, small in size, high in reliability and capable of achieving high-sensitivity measurement of the C4F7N gas decomposition products.

The invention discloses a C4F7N gas optical fiber Fabry-Perot sensor, a sensitivity demodulation system and a sensitivity demodulation method, belongs to the technical field of C4F7N gas detection, and solves the problem of how to improve the sensitivity of the C4F7N gas optical fiber Fabry-Perot sensor. A Fabry-Perot cavity is formed by a gap between the end face of a single-mode optical fiber of the C4F7N gas optical fiber Fabry-Perot sensor and the surface of a groove; emergent light of the single-mode optical fiber is reflected by the surface of the groove, and the groove converges the reflected light, so that the loss of the reflected light is reduced, and the detection sensitivity of the sensor is improved; the sensor is simple in structure, small in size and high in reliability; according to the sensitivity demodulation system, the resonant wavelength drift direction is judged based on a twice multi-frequency correlation demodulation method, and then the sensitivity of the sensor is represented according to a peak value tracking method; the cavity length of the sensor can be demodulated by only one enveloped wavelength range, so that the requirement on the bandwidth of a light source is reduced, and the equipment investment cost is reduced.

Silicon photonics technologies adds integrated optics functionality to CMOS integrated circuits thereby leveraging high volume manufacturing. Independent of geometry or technology these silicon photonic devices require packaging with single mode optical fibers to interface to the optical network and / or co-packaging with active semiconductor devices, discrete microoptoelectromechanical systems (MOEMS) s or monolithically integrated MOEMS. Stringent performance constraints and minimizing manufacturing costs / times are consistent demands on such photonic circuits. Accordingly, there is a demand for low-cost and low-loss optical coupling technologies for packaging that can easily be scaled for mass production that overcome limitations in the prior art. The inventors have established design methodologies, packaging schemes and component designs that leverage automated passive assembly techniques for speed / cost in combination with directly written optical interconnects that allow for offsetting the losses that would arise from the manufacturing tolerances of these passive assembly techniques.

The invention relates to an all-fiber sub-hundred femtosecond laser based on an SESAM. The all-fiber sub-hundred femtosecond laser comprises the SESAM, a wavelength division multiplexer, a pumping source, a pumping protector, a gain fiber, a chirp fiber bragg grating, an isolator, a reflector, a compression unit and an autocorrelator. According to the invention, the chirp fiber bragg grating with the dispersion amount of 0.115 ps / nm is adopted to compensate positive dispersion in the cavity, so that mode-locked pulse with the spectral width of 23nm is realized. A transmission-type diffraction grating pair is adopted, the pulse width is compressed to 88fs, and the maximum spectral width 27nm is obtained under the dispersion of 0.00087 ps2 in a near-zero cavity. The condition that the optimal spectral bandwidth of the optimal seed source pulse based on the optical fiber chirped pulse amplification laser should be larger than 15 nm is met, and the compression pulse distortion of the amplifier is reduced. By adopting the linear cavity, the SESAM is adhered to the surface of the single-mode optical fiber patch cord for starting mode locking, so that an all-optical-fiber structure of the system is realized, and the single-mode optical fiber patch cord is suitable for industrial integrated application.

The invention belongs to the technical field of optical fiber sensing, and discloses a high-temperature-resistant and high-pressure-resistant multi-parameter integrated sensor and system based on optical fiber dislocation welding, and the sensor comprises a packaging main body, and the center of the packaging main body is provided with a center hole and a cavity which are used for accommodating a transmission optical fiber. The tail end of the transmission optical fiber is sequentially connected with a temperature detection device and a pressure / sound detection device which are positioned in the cavity; the temperature detection device comprises a fiber bragg grating; the pressure / sound detection device comprises a single-mode fiber, a multimode fiber, a first hollow capillary fiber and a second hollow capillary fiber which are connected in sequence; the axes of the first hollow capillary optical fiber and the second hollow capillary optical fiber are connected in a staggered manner to form an open structure. The pressure / sound-temperature multi-parameter composite in-situ synchronous measurement device realizes composite in-situ synchronous measurement of multiple parameters of pressure / sound-temperature, has the advantages of high temperature resistance, small size and high test precision, and has wide application prospects in the fields of aerospace, petroleum metallurgy, environmental monitoring and the like.

The invention belongs to the technical field of deformation measurement, and provides a distributed optical fiber sensing casing damage monitoring system and monitoring method based on an OFDR (Optical Frequency Domain Reflectometer) technology. An armored optical cable consisting of a multi-core single-mode optical fiber and two multi-mode optical fibers of which the tail ends are welded into a U shape is spirally wound on the outer wall of a casing; a single-channel DSS / dual-channel DTS modulation-demodulation system of a dynamic distributed optical fiber strain and temperature composite sensing technology is used for real-time acquisition of strain and temperature sensing data of the casing pipe under the action of ground stress, and a cylindrical casing pipe three-dimensional model reconstruction algorithm is combined to automatically generate a spiral line. The three-dimensional model of the cylindrical casing is in one-to-one correspondence with the position of the optical fiber on the real casing, casing damage possibly occurring to the underground casing under the action of ground stress is monitored and measured in real time for a long time, early warning and forecasting information about that the casing damage is about to occur or is occurring is issued in time, and well site operators can conveniently handle and repair the casing damage in time.

The invention discloses a polarization-state-based optical fiber vibration sensing system and application, and relates to the technical field of optical fiber sensing, and the polarization-state-based optical fiber vibration sensing system mainly comprises a transmitting end and a receiving end. The transmitting end comprises a laser diode, a first erbium-doped optical fiber amplifier, a first circulator, a polarization scrambler, a single-mode optical fiber link, a second circulator and a second erbium-doped optical fiber amplifier which are connected in sequence; and the receiving end comprises a polarization beam splitter, a first shunt module, a second shunt module, an optical mixer, a first balanced photoelectric detector, a second balanced photoelectric detector, a third balanced photoelectric detector and a polarization analysis module. According to the optical fiber vibration sensing system based on the polarization state and the application, the vibration monitoring performance and reliability in a long-distance and high-noise environment can be improved.

The invention describes an apparatus that implements efficient coupling between a photonic integrated circuit (PIC) and a second optical element such as a fiber or laser, while at the same time allowing for efficient polarization management and / or optical isolation. It enables the packaging of PICs with large single mode fiber counts and in- and out-coupling of light with arbitrary polarization. The apparatus comprises a glass interposer that contains at least one polarization selective element together with a pair of lenses transforming a beam profile between the 2nd optical element and a polarization selective coupler on the PIC. The invention also comprises a method for fabricating the apparatus based on a subassembly of building blocks that are manufactured using wafer-scale high-precision glass-molding and surface treatment(s) such as thin-film coating.

The invention discloses a photonic integrated circuit chip and a silicon optical integration platform, and aims to provide a specific waveguide structure on the photonic integrated circuit chip to realize efficient coupling with a common single-mode fiber, and meanwhile, a suspended structure is not introduced, so that the overall structure has relatively high mechanical stability. The method can pass high-temperature and high-humidity reliability test conditions of the photon integrated circuit chip, and is compatible with reflow soldering, silicon through hole and other processes.

The invention discloses an ultrahigh resolution interferometer measurement method and system based on a phase shift gauge block, and the method comprises the steps: placing an ultrahigh resolution interferometer and a preset phase gauge block in a heat preservation box, and introducing two kinds of frequency stabilization laser into the heat preservation box through a single-mode optical fiber; obtaining interference fringe data by adopting a five-step phase shift method, and adjusting the interference fringe data according to the laser wavelength to obtain adjusted data; acquiring environmental data containing the preset phasor block in the heat preservation box, and correcting the adjustment data by eliminating change influence based on the environmental data to obtain corrected data; determining the length of the preset phasor block according to the decimal number of the interference fringes and the integer series of the interference fringes under different wavelengths through a multi-wavelength decimal superposition method, obtaining the measurement data of the Korotkoff interferometer, carrying out the adaptive compensation of the phase shifter, correcting the length according to the uncertainty of the measurement data, and obtaining the phase of the Korotkoff interferometer. The output is a measurement result.

The invention discloses a fiber bragg grating femtosecond laser direct writing system and method based on light field regulation and control. The system comprises a femtosecond laser source, a polarization control module, a light beam expanding module, a light field modulation module, a 4f filtering imaging module, an oil immersed objective lens, a precision positioning and optical fiber clamping module, an observation module and a computer control module. The method comprises the following steps: firstly, fixing a standard single-mode optical fiber to be processed on a three-dimensional precision displacement platform; then programmable wavefront modulation is carried out on the femtosecond laser through a light field modulation module, and a multi-focus array is generated; then focusing the multi-focus array into the fiber core through an oil-immersed objective lens to realize one-time parallel inscribing of a plurality of refractive index modulation RIM regions; and finally, the computer control module controls the three-dimensional precision displacement platform to move at a constant speed in the axial direction of the optical fiber, and parallel integrated inscribing of a plurality of FBG structures is completed. According to the invention, the inscribing precision and inscribing efficiency of fiber bragg grating femtosecond laser direct writing are improved.

The invention discloses a multi-parameter C4F7N gas detection optical fiber Fabry-Perot sensor with a temperature compensation function, belongs to the technical field of C4F7N gas detection, and solves the problems that an existing optical fiber sensing instrument is low in sensitivity and single in application scene. When the sensor is in an environment with target gas, a detection result of the environment gas and a detection result of the temperature can be obtained, so that the application range of the sensor is widened; the gap between the end face of the single-mode fiber and the surface of the groove forms a Fabry-Perot cavity, emergent light of the single-mode fiber is reflected by the surface of the groove, the groove converges the reflected light, the reflectivity is improved, the reflected light is efficiently coupled into the single-mode fiber, the contrast ratio of a light interference peak is improved, and then the detection sensitivity of the sensor is improved. The sensor is simple in structure, small in size, high in reliability and capable of achieving high-sensitivity measurement of the C4F7N gas decomposition products.

The invention discloses an integrated optical diversity receiving device, solves the problem of high power consumption when the influence caused by phase distortion and light beam pointing error is corrected in the existing free space optical communication, and belongs to the field of optical communication. The method comprises the steps that free space light focused by a lens is received by a multimode / few-mode optical fiber; the multi-mode light beams received by the multimode / few-mode optical fiber enter the photon lantern; the photon lantern is coupled to the single-mode fiber array after mode demultiplexing; each light beam in the single-mode fiber array enters a polarization beam splitting rotary combiner through an edge coupler; the polarization beam splitting rotation combiner performs transverse electric wave (TE) and transverse magnetic wave (TM) mode separation on the entered light beam, then rotates the separated TM polarization state light to a TE polarization state, combines the rotated TE polarization state light and the separated TE polarization state light, and then enters the MZI network; the MZI network is used for realizing optical coherent beam combination; a control circuit controls the merging of the light beams in the MZI network.

The invention discloses a method of an optical anti-turbulence device for polarization multiplexing spatial optical communication. The mode demultiplexer is connected with the optical fiber; the single-mode optical fiber array is respectively coupled with each spatial intrinsic mode decomposed by the mode demultiplexer; the polarization CBC chip is connected with the other end of the single-mode optical fiber array; the driving control module is connected with the polarization CBC chip; the polarization multiplexing optical communication digital coherent receiver (Rx) is connected with the polarization CBC chip through a single-mode optical fiber; through the arrangement of the polarization CBC chip, the compatibility of a polarization multiplexing technology and a mode multiplexing coherent beam combination technology is realized, the problem of polarization dimension information loss or strong crosstalk caused by the use of a polarization state rotator (PSR) and a polarization maintaining optical fiber in the prior art is solved, modulation information of two orthogonal polarization dimensions is completely reserved, the communication bandwidth is improved, and the communication efficiency is improved. And the communication efficiency is greatly improved.

The invention relates to a combined optical fiber and a preparation method, and relates to the technical field of optical fiber preparation, and the combined optical fiber comprises an anti-resonance hollow-core optical fiber having a first mode field diameter; the single-mode optical fiber has a second mode field diameter, and the first mode field diameter is larger than the second mode field diameter; one end of the bridging optical fiber is connected with the anti-resonance hollow-core optical fiber and is matched with the mode field of the anti-resonance hollow-core optical fiber, and the other end of the bridging optical fiber is connected with the single-mode optical fiber and is matched with the mode field of the single-mode optical fiber. The anti-resonance hollow-core optical fiber and the single-mode optical fiber are connected through the bridging optical fiber, and the two ends of the bridging optical fiber are matched with the anti-resonance hollow-core optical fiber and the single-mode optical fiber respectively, so that compared with a direct fused biconical taper single-mode optical fiber, the bridging optical fiber is lower in operation difficulty, better in connection performance and capable of being replaced even if misoperation occurs, and the combined optical fiber is convenient to prepare; the problem that in the prior art, a combined optical fiber with an anti-resonance hollow-core optical fiber is difficult to prepare conveniently is solved.

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 invention discloses an optical fiber probe imaging catheter module for an intravascular frequency domain OCT (optical coherence tomography) imaging system, which comprises a transparent protective sleeve and a lining tube arranged in the transparent protective sleeve, a transparent window is arranged at the front end of the transparent protective sleeve, and a single-mode optical fiber, a coreless optical fiber, a GRIN (gradient refractive index) lens and a reflector are sequentially arranged in the lining tube. And a torsion spring tube is arranged outside the single-mode optical fiber. The design of the optical fiber probe and the double-layer catheter is optimized, the imaging resolution is improved, the adaptability of the probe and tissue is enhanced, the optical signal transmission efficiency is improved, high-resolution and low-friction intravascular imaging is provided, and the OCT image quality and reliability are improved.

The invention belongs to the technical field of pavement monitoring methods, and particularly discloses a distributed optical fiber permanent deformation monitoring method for an asphalt pavement under a moving load. The method comprises the following steps: laying a single-mode optical fiber in a test piece; laying a full-bridge strain gauge in the test piece; monitoring an optical fiber vibration signal of the test piece during the movement of a test wheel and a strain change of the test piece during the movement of the test wheel in real time through a strain acquisition instrument; processing the optical fiber vibration signal and the strain change by using matlab data analysis software; analyzing the data change trend according to the processed optical fiber vibration signal and the strain change, and establishing a mathematical relationship between the two; and according to the mathematical relationship, distributed monitoring of the permanent deformation of the asphalt pavement under the moving load by the optical fiber vibration signals is realized. By the adoption of the bituminous pavement distributed optical fiber permanent deformation monitoring method under the moving load, real-time, dynamic, large-range, long-distance and high-precision monitoring of bituminous pavement permanent deformation is achieved, and the defects in the prior art are overcome.

The invention discloses a vernier effect and Sagnac ring-based dual-parameter optical fiber sensor, which belongs to the technical field of optical fiber sensors and comprises a broadband light source SLED (1), a coupler (2), a sensing structure A (3), a circulator (4), a sensing structure B (5) and a spectrum analyzer (6). The device comprises a first single-mode fiber (301), a polarization-maintaining photonic crystal fiber (302), a few-mode fiber (303), a fiber Bragg grating (304), a second single-mode fiber (501), a first hollow-core fiber (502) and a second hollow-core fiber (503). Parasitic interference is avoided by grinding the end face of the hollow-core optical fiber, and the reliability of the sensor is improved; two transmission peaks appear on the fiber bragg grating inscribed on the few-mode fiber through different mode numbers in the few-mode fiber, and gas concentration and temperature sensitivity of two signals can be calculated by observing drifting of the transmission peaks; an optical vernier effect can be formed through superposition of a Sagnac interferometer formed by polarization-maintaining photonic crystal fibers and an F-P interferometer formed by hollow core dislocation, and the gas concentration and the temperature sensitivity of the sensor are improved. The sensor has the characteristics of high sensitivity, wide measurement range, simple structure, small size and the like.

The invention relates to the technical field of coupling alignment of single-mode optical fibers, in particular to an optical fiber coupling alignment method and system based on wavefront aberration and a sensitivity matrix. The system comprises an optical measurement module, a processing and control module and a multi-axis precision adjustment platform, and the alignment method comprises the steps that firstly, an interference fringe image is obtained and processed through an interference light path, continuous wavefront is recovered through Fourier transform and phase unwrapping, and a Zernike coefficient for quantizing wavefront distortion is obtained through Zernike polynomial fitting. A sensitivity matrix representing the linear relation between the degree-of-freedom adjustment amount and Zernike coefficient changes is established and serves as a physical guide item to introduce a speed updating formula of a particle swarm optimization algorithm, an SG-PSO algorithm is formed, a particle swarm is guided to conduct directional intelligent search and rapidly output the optimal adjustment amount, and finally a multi-axis precision adjustment platform is driven to complete alignment. According to the method, optimization of wavefront sensing and physical model guiding is effectively fused, and the convergence speed, the alignment precision and the global search capability are remarkably improved.

The invention relates to the technical field of photoelectric composite cables, in particular to a cold-resistant tensile photoelectric composite cable and a rapid laying method thereof, and the cable comprises a conductor part, an insulating layer, an optical fiber unit, a filling layer and an outer sheath which are coaxially arranged from inside to outside and are sequentially wrapped. The conductor part is formed by twisting a plurality of strands of copper wires, a carbon fiber reinforced core is arranged in the conductor part, and the insulating layer is made of EAA and PEBA blending modified materials and contains nano boron nitride particles; the optical fiber unit is of a PBT loose tube structure, a plurality of single-mode optical fibers and special ointment are arranged in the PBT loose tube structure, micro-nano protrusions are arranged on the inner wall of a loose tube, and the surface of each micro-nano protrusion is covered with a silicon dioxide antireflection film. The cable integrates the functions of cold resistance, stretch resistance, electric conduction, insulation, communication, heat dissipation and protection. The insulating layer adopts EAA and PEBA blending modified materials to be combined with nano boron nitride particles, so that the cold resistance and the insulativity are improved; and the polyurethane elastomer of the filling layer is compounded with the glass beads, so that the structural stability and the comprehensive performance are enhanced.

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 discloses a double-core optical fiber integrated MZ interferometer based on thermal diffusion. The interferometer is mainly characterized in that a core structure of the interferometer is formed by sequentially welding an input optical fiber (1), a first double-cladding transition optical fiber (2), a double-core optical fiber (3), a second double-cladding transition optical fiber (4) and an output optical fiber (5). Thermal diffusion treatment is performed by long-term high-temperature heating in the welding regions (A) and (B). The thermal diffusion treatment enables fiber core doping elements to be diffused, a transition area is formed in the double-clad optical fiber, the coupling efficiency between the single-mode optical fiber and the double-core optical fiber is remarkably improved, and compared with a traditional tapering structure, the thermal diffusion area is higher in mechanical strength. The interferometer device is compact in structure, high in integration level and excellent in interference contrast, can realize high-precision phase sensitive sensing, is suitable for distributed measurement of physical quantities such as temperature, bending and refractive index, and can be widely applied to optical fiber sensing.

The invention discloses a method for measuring fan blade root stress based on a fiber bragg grating sensor. According to the method, 6-10 key measurement points are selected in a blade root area of a fan blade, a pair of FBG sensors is installed at each measurement point, one FBG sensor is used for stress measurement (affected by strain and temperature at the same time), the other FBG sensor is used for temperature compensation, and decoupling of temperature and strain signals is achieved. The system adopts a single-mode optical fiber, a broadband light source (the wave band is 1525-1565 nm, and the power is 10-20 mW) and a high-resolution spectrum analyzer (the resolution is smaller than or equal to 1 pm, and the sampling rate is larger than or equal to 100 Hz or 1 kHz) to collect optical signals reflected by an FBG sensor in real time, measured wavelength shift is converted into accurate strain data through temperature compensation and a strain calculation formula, and the optical signals are transmitted to the FBG sensor. And calculating a stress value by combining the Young modulus and Poisson's ratio of the material. The method has the advantages of being high in precision, high in real-time performance, resistant to electromagnetic interference and suitable for seaborne, high-altitude and other severe environments, and reliable data support can be provided for dynamic stress monitoring, fatigue life prediction and fault early warning of the fan blade.

According to the recoverable self-adaptive traffic signal lamp control system, the traffic management level is remarkably improved. According to the system, through a multi-information acquisition layer, various sensors are deployed at key road sections, and traffic data are accurately acquired in combination with the Internet of Vehicles and a high-precision positioning technology. And the high-speed stable transmission layer is connected with 5G and 4G networks through a single-mode optical fiber, so that stable transmission of data is guaranteed. And the intelligent data processing layer applies 3D convolution, a CNN model of an attention mechanism and a data fusion algorithm to deeply analyze data and generate a congestion index. The optimization decision generation layer constructs a reward function according to the key indexes, generates an optimal timing scheme through a reinforcement learning algorithm, and gives consideration to the passage of special vehicles. And the precise control execution layer adjusts and controls the signal lamp by using gradient brightness. The intelligent energy management layer is powered by solar energy. Once a system fault occurs, the fault fast recovery layer switches the standby device in a short time, and the timing is recalculated based on the multi-source data. The system effectively relieves congestion, enhances stability and reliability, and also can reduce energy consumption.

The invention discloses an FPI and MZI optical fiber sensor based on a PDMS microcavity and application thereof, relates to the technical field of optical fiber sensors, and aims to solve the problem of lack of an optical fiber sensor with a double-effect cooperative regulation mechanism in the prior art. According to the technical key points, the FPI and MZI optical fiber sensor based on the PDMS microcavity is composed of a first single-mode optical fiber, a multimode optical fiber, the PDMS cavity and a second single-mode optical fiber which are connected in sequence, the first single-mode optical fiber and the multimode optical fiber are welded, the microcavity exists between the multimode optical fiber and the second single-mode optical fiber, PDMS is injected into the microcavity to form the PDMS cavity, and the PDMS cavity is connected with the PDMS microcavity. One end, far away from the PDMS cavity, of the second single-mode optical fiber is a cutting end surface; the critical surface of the multimode optical fiber and the PDMS cavity is a reflector 1, the critical surface of the second single-mode optical fiber and the PDMS cavity is a reflector 2, and the reflector 1 and the reflector 2 form a Fabry-Perot interferometer. The sensor combines the working principles of FPI and MZI, and can realize accurate measurement of temperature.

The invention discloses a linear light spot multi-pass optical fiber photoacoustic gas sensor for gas insulation equipment, belongs to the technical field of sensing and measuring of operation and maintenance of power transmission and transformation equipment, and solves the problems that an existing optical fiber photoacoustic trace gas detection instrument is large in size and not beneficial to miniaturization. Modulated excitation light of the sensor enters a rectangular gas chamber with a high-reflectivity plano-concave reflector, and is reflected for multiple times in the gas chamber to form linear light spot distribution, so that a photoacoustic signal is generated; the probe light reflected by the tail end of the cantilever beam etched on the sound wave sensitive cantilever beam diaphragm, the end face of the tail end of the single-mode optical fiber and the reflected probe light generate a Fabry-Perot interference effect, so that the concentration of the gas is detected; the volume of the rectangular air chamber is greatly reduced, so that the size of the whole sensing probe is reduced, and the sensor has the advantages of small volume, high sensitivity, intrinsic safety and the like.

The invention relates to the technical field of optical fiber sensors, and provides an optical fiber cranium temperature and cranium pressure composite monitoring probe and a preparation method thereof.The optical fiber cranium temperature and cranium pressure composite monitoring probe comprises a pressure diaphragm, a hollow glass tube, a metal coating, a graded-index optical fiber and a single-mode optical fiber, one end of the hollow glass tube is connected with the pressure diaphragm; the metal coating is arranged on one surface, far away from the hollow glass tube, of the pressure diaphragm; the graded-index optical fiber is arranged in the hollow glass tube, and the graded-index optical fiber and the pressure diaphragm are spaced to form an F-P cavity; and one end of the single-mode optical fiber is inserted into the hollow glass tube. The corrugated pressure diaphragm formed by processing the coreless optical fiber is used as a sensitive element, the pressure measurement sensitivity can be greatly improved under the condition of the same diaphragm thickness and diameter, the zero drift of the sensor caused by temperature and moisture is reduced, and meanwhile, the pressure sensitivity can be accurately regulated and controlled so as to adapt to different application scenes such as intracranial pressure, intramental pressure and blood flow pressure.

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 discloses a dual-wavelength microsphere laser based on tri-doped rare earth ions and a preparation method thereof, the dual-wavelength microsphere laser based on tri-doped rare earth ions comprises a silica fiber, the middle part of the silica fiber is provided with a conical region; the pump light source is arranged at one end of the silica fiber; the erbium, holmium and ytterbium tri-doped tellurate glass microspheres are arranged in the conical region; pump light emitted by the pump light source is guided to the conical region through the single-mode optical fiber and is optically coupled with the erbium-holmium-ytterbium tri-doped tellurate glass microsphere; in the erbium-holmium-ytterbium triple-doped tellurate glass microspheres, infrared-transmitting tellurate glass is used as a matrix, and the doping amount of an erbium element is 0.11%, the doping amount of a holmium element is 0.22%, and the doping amount of an ytterbium element is 0.80% in percentage by mass. According to the dual-wavelength microsphere laser based on the three-doped rare earth ions, efficient and stable dual-wavelength laser output is achieved.