190 results about "Multi-mode optical fiber" patented technology

The invention discloses an optical fiber transmission image recovery method and device based on a complex amplitude regulation metasurface diffraction device, and the method comprises the steps: obtaining the complex amplitude distribution of each diffraction layer through the training of a diffraction neural network, designing a corresponding metasurface array, and preparing a cascaded metasurface diffraction device with a complex amplitude regulation function, deploying a cascade metasurface diffraction device to the far end of the multimode optical fiber and performing complex amplitude modulation on emergent circularly polarized light to realize high-resolution or high-sampling-rate image recovery; or an optical fiber transmission inverse matrix is solved by using an analytical method, and a corresponding metasurface array is designed, so that the single-layer metasurface diffraction device with a complex amplitude regulation and control function is prepared; and deploying the single-layer metasurface diffraction device to the far end of the few-mode optical fiber and carrying out complex amplitude modulation on emergent circularly polarized light to realize low-resolution or low-sampling-rate image recovery. Miniaturization of a multimode optical fiber imaging system can be realized, and the image recovery quality is effectively improved based on complex amplitude modulation of the metasurface diffraction device.

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 multimode optical fiber imaging method based on a double-encoder network and an attention mechanism. A parallel double-encoder structure is formed by combining a Transform encoder and a convolution encoder, and meanwhile, a CBAM attention mechanism is introduced, so that a DEANet network model is constructed. According to the method, a convolution encoder is adopted to capture local details, and meanwhile, a Transform encoder is utilized to establish global feature association and high-frequency feature distribution to make up for the problem that the sensing range is limited. In addition, collaborative extraction and fusion of multi-scale information of channels and spaces are performed in a feature space through an attention module (CBAM). Compared with a traditional convolutional network, the method has the advantages that local details and a global structure are considered, high-fidelity reconstruction of a complex target structure and edge details in multimode optical fiber imaging is realized, and good robustness is kept after system disturbance.

The invention discloses an optical fiber dislocation temperature sensor and a preparation method thereof. The optical fiber dislocation temperature sensor comprises a dislocation optical fiber integrated with a photoresist film layer. The staggered optical fiber integrated with the photoresist film layer comprises a staggered optical fiber and a photoresist film layer covering a staggered area of the staggered optical fiber; the dislocation optical fiber is composed of a first multi-mode optical fiber, a second multi-mode optical fiber and a third multi-mode optical fiber which is welded between the first multi-mode optical fiber and the second multi-mode optical fiber in a dislocation mode. The staggered optical fiber is prepared through the optical fiber melting technology, the staggered area of the staggered optical fiber is coated with the SU-8 photoresist with the high thermo-optical coefficient and the high thermal expansion coefficient to form the photoresist film layer, high-sensitivity temperature sensing detection is achieved, the size is small, the preparation process is simple, and the sensor is suitable for biomedical treatment, medical treatment and the like. Wide application prospects are realized in the fields of aerospace, industry and agriculture and the like.

The invention discloses a multimode optical fiber anti-disturbance real-time imaging method based on a double-neural network architecture, which comprises the following steps: firstly, acquiring a speckle image of a target image subjected to multimode optical fiber scattering transmission under a multi-disturbance dynamic state, then extracting spatial domain and frequency domain information of the speckle image, and training through an SFNet classification network to obtain a disturbance dynamic state classification model; and training by using a U-Net imaging network to obtain a speckle imaging model. During testing, the multimode optical fiber disturbance state corresponding to the speckle image is judged by using the classification model, and then the speckle image is input into the speckle imaging model under the corresponding multimode optical fiber disturbance state for reconstruction. According to the method, accurate classification and high-quality reconstruction of the speckle image of the multimode optical fiber under the multi-disturbance condition are achieved, good real-time performance and anti-interference performance are achieved, and the method is suitable for dynamic optical fiber imaging in the complex environment.

The invention relates to a method and a system for realizing fast and uniform focusing of emergent light spots of a multi-mode optical fiber based on superpixels, belongs to the technical field of novel optical imaging and light field regulation and control, and integrates online speckle acquisition, offline amplitude optimization and an online speckle acquisition stage. When a certain modulation area is in an activated state, respectively capturing a non-interference speckle image of the emergent end of the multimode optical fiber and an interference speckle image generated when the area and the reference area are activated at the same time, and traversing all the modulation areas to totally obtain a speckle image; in the off-line amplitude optimization stage, a focusing light spot is preset, and calculation is carried out by utilizing intensity information of a corresponding focusing position in the speckle image. And analyzing all the focusing light spots one by one so as to construct a binary amplitude modulation mask. And the masks are loaded to the spatial light modulator one by one, so that accurate point-by-point focusing of N emergent light spots of the multimode optical fiber is realized, and the focusing efficiency and uniformity are greatly improved.

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 an optical fiber coupling real-time correction method in a single-mode and multi-mode optical fiber endoscopic imaging system, which comprises the following steps of: firstly, manually adjusting reflectors M1 and M2 to an optimal multi-mode optical fiber coupling state, acquiring images of light spots at the near end and the far end of a laser beam in the state by using a CCD (charge coupled device) 1 and a CCD 2, and calculating the position of a central coordinate of the images; and collecting a speckle image formed by the light spot through the scattering medium by using a CCD3 (charge coupled device 3). The system monitors the center coordinates of near-end and far-end light spots at the current moment and the correlation coefficient of the current speckle image and the collimation state image in real time. The piezoelectric mirror bracket is fed back and adjusted in real time through the center coordinates of the two spot light spots and the correlation coefficient of the speckles, so that the correlation coefficient of the speckles is kept above a set threshold value, and automatic calibration of light beams is achieved. On the basis of the traditional thinking that two points determine one straight line, the correlation coefficient of using speckles is increased, the alignment precision is improved, and the method has certain practicability and application prospects.

The invention discloses an optical measurement device for an engine flow field, and relates to the technical field of optical measurement. The transmitting end module and the receiving end module are arranged on two walls of an engine to be tested and are provided with opposite lens type end caps; the transmitting end module comprises a built-in metal coating high-temperature single-mode optical fiber; one end of the single-mode optical fiber is connected with a lens type end cap of the transmitting end module to form an integrated laser transmitting probe; the receiving end module comprises a built-in metal coating high-temperature multimode optical fiber and a detector; one end of the multimode optical fiber is connected with a lens type end cap of the receiving end module to form an integrated laser coupling probe; and a receiving and transmitting light path pair penetrating through an engine combustion area is formed between the lens type end caps of the transmitting end module and the receiving end module. Water vapor between a window sheet and an optical probe collimating lens and between the collimating lens and an optical fiber core in a traditional measurement module is eliminated, and the measurement precision of an engine flow field combustion area is improved.

The embodiment of the invention provides a signal cable, a signal monitoring system and a signal monitoring method. The signal cable comprises a plurality of conductors, a plurality of insulators, an optical fiber sensing layer, a pressure-resistant buffer layer, a shielding layer and an outer sheath layer, wherein each conductor is wrapped with one insulator, and the plurality of insulators are included in the optical fiber sensing layer; a first single-mode optical fiber, a second single-mode optical fiber and a multimode optical fiber are arranged in the optical fiber sensing layer, and the first single-mode optical fiber, the second single-mode optical fiber and the multimode optical fiber are circumferentially arranged in the optical fiber sensing layer; the compression-resistant buffer layer is wrapped on the optical fiber sensing layer, the shielding layer is wrapped on the compression-resistant buffer layer, and the outer sheath layer is wrapped on the shielding layer. Through cooperation and distributed sensing of multiple optical fibers in the optical fiber sensing layer, the transmission precision and distance of cable signals are effectively improved, and the safety and reliability are improved.

The present invention relates to a multispectrum endoscope and an endoscope system comprising same. The multispectrum endoscope of the present invention comprises: a first light source emitting infrared rays having a plurality of wavelengths; a plurality of multimode optical fibers for guiding the infrared rays emitted from the first light source toward a sample; a second light source emitting a visible ray; an optical fiber for guiding the visible ray emitted from the second light source toward the sample; a lens part for receiving a fluorescent signal emitted from the sample and a visible light signal reflected off the sample; and an optical fiber bundle for guiding the fluorescent signal and / or the visible light signal received by the lens part toward a multispectrum photodetector, wherein the optical fiber bundle is disposed so as to be surrounded by the plurality of multimode optical fibers, and the end portion of the multispectrum endoscope emitting the visible ray surrounds at least a portion of the plurality of multimode optical fibers.

The invention discloses a laser synchronous transmission system and method based on a rotary motion mechanism and application, and belongs to the technical field of laser wireless energy transmission. The system comprises a static end and a rotary end of which the geometric centers are located on the same rotation axis; the static end is provided with a multimode optical fiber used for transmitting laser energy and a transmitting end single-mode optical fiber used for transmitting laser signals, the transmitting end single-mode optical fiber is provided with a transmitting end optical fiber collimator group, and the output of the multimode optical fiber is sequentially connected with a square optical fiber array and a lens array; the rotating end is provided with a laser cell panel for receiving laser energy, a receiving end optical fiber collimator for receiving laser signals and a receiving end single-mode optical fiber; and the square optical fiber array is connected to the transmitting end optical fiber collimator group. According to the invention, the stability and anti-interference performance of energy and signal cooperative transmission in the rotating mechanism are improved, the processing and assembling difficulty is reduced, the reliability of the system in a complex environment is improved, and long-term stable cooperative operation of higher-power laser and high-speed communication is supported.

The invention provides a multi-parameter optical fiber sensing submarine cable for safety monitoring of a deep sea riser and a monitoring system, and relates to the technical field of ocean optical cables, the multi-parameter optical fiber sensing submarine cable comprises a central reinforcing core, and an inner cladding, an inner sheath, an outer cladding and an outer sheath which sequentially cover the periphery of the central reinforcing core from inside to outside, the inner cladding comprises a plurality of inner layer sensing units, and the outer cladding comprises a plurality of outer layer sensing units; the plurality of inner-layer sensing units are distributed in an annular array, each inner-layer sensing unit comprises any one of a single-mode optical fiber, a weak grating array and a multimode optical fiber, the peripheries of the single-mode optical fiber, the weak grating array and the multimode optical fiber are all coated with a first fiber paste layer, and the periphery of the first fiber paste layer is coated with a first stainless steel pipe; the inner wrapping layer comprises outer layer sensing units and armored steel wires, the outer layer sensing units and the armored steel wires are distributed in an annular array, a plurality of armored steel wires are arranged between any two adjacent outer layer sensing units, and each outer layer sensing unit comprises a first fiber grating array and a second fiber grating array. According to the invention, the monitoring precision of the submarine cable on the marine oil and gas riser can be improved.

The invention discloses an unmanned aerial vehicle endurance energy supply system and method based on optical fibers, and belongs to the technical field of power transmission line unmanned aerial vehicle inspection. The system comprises a ground laser source, an optical fiber link and an unmanned aerial vehicle library arranged on a power transmission tower; the ground laser source generates laser, the laser is sent to the unmanned aerial vehicle garage through the optical fiber link, and the unmanned aerial vehicle garage converts the laser into electric energy for charging the unmanned aerial vehicle; unmanned aerial vehicle inspection data is sent to a ground laser source from an unmanned aerial vehicle library through an optical fiber link, and the ground laser source collects the inspection data to a main station; the optical fiber link comprises a multimode optical fiber with a set core diameter and a beam splitter, one end of the multimode optical fiber with the set core diameter is connected with a coupler of the ground laser source, the other end of the multimode optical fiber with the set core diameter is connected with the beam splitter, and the output of the beam splitter directly faces the packaged photocell. The optical fiber is used as an energy transmission medium, energy is sent to the unmanned aerial vehicle hangar along with an optical fiber link, and light energy is converted into electric energy in the unmanned aerial vehicle hangar.

A waveguide grating coupler (WGC) for coupling light transmitted between an integrated optical waveguide and an optical fiber and a method for making the waveguide grating coupler are provided. The waveguide grating coupler working for dual polarization includes a grating layer having a first plurality of etched holes and an overlay layer disposed on the grating layer, having a second plurality of etched holes. At least one of the second plurality of etched holes partially overlaps a corresponding etched hole of the first plurality of etched holes. The overlay layer is configured to create a shift of every period of grating to the grating layer to achieve upwards constructive interference and downwards destructive interference of light such that coupling efficiencies of both vertical grating coupling and angle coupled grating coupling are enhanced for a single mode optical fiber, a few mode optical fiber, or a multi-mode optical fiber.

The invention relates to the field of optical fiber sensing, in particular to a multichannel optical fiber surface plasma resonance sensing probe as well as a preparation method and application thereof. According to the multichannel optical fiber surface plasma resonance sensing probe, the sensing probe adopts an end face reflection type optical fiber sensing structure, and the end face reflection type structure is formed by welding a multimode optical fiber and a coreless optical fiber. A multimode-coreless optical fiber welded end face reflection type structure is adopted, SPR signals are excited through end face total reflection, the defect that a traditional lateral coupling type optical fiber SPR sensor is difficult to carry out directional detection in narrow spaces (such as blood vessels and tissue gaps) is overcome, miniaturized insertion type diagnosis with the minimum diameter being 300 micrometers is achieved, and the SPR sensor is suitable for in-situ monitoring of living tissue; according to the invention, through the nanocluster modification layers (0 / 2 / 4 layers) which are axially distributed at intervals, multi-channel functionalization can be completed only by a pulling method, traditional micro-nano processing and a complex film layer structure are not needed, and the preparation time of the multi-channel sensor is shortened from gt to gt; and the time is shortened from 6 hours to 1 hour.

The invention discloses an integrated distributed optical fiber sensing extra-high voltage live working sling on-line monitoring system, and relates to the technical field of electric power safety monitoring, and the system comprises a multilayer flexible insulating sling body with a spiral staggered optical fiber embedding channel; the multimode optical fiber sensing unit is embedded in the channel and comprises a Bragg grating array and a Brillouin scattering optical fiber; the stress identification module is used for constructing a heat-force coupling response matrix and identifying a stress concentration area; the digital twin modeling module is used for constructing a local finite element sub-model and outputting a fatigue trend curve; the diagnosis feedback module is used for generating a sling risk level signal and realizing remote control linkage; the system can monitor the stress evolution and fatigue damage conditions of the sling structure in real time, has the advantages of high strain identification precision, accurate fatigue trend prediction, timely remote response and the like, and improves the safety and intelligent management level of extra-high voltage live working.

The invention is suitable for the technical field of wavelength measurement, and provides a speckle wavelength measurement device with miniaturization and strong anti-interference, which comprises a single-mode fiber, a dislocation welding multimode fiber, a CCD (Charge Coupled Device) camera and a computer which are sequentially arranged along a light path, the single-mode optical fiber is connected with the dislocation welding multimode optical fiber; the dislocation welding multimode optical fiber is formed by a first short multimode optical fiber and a second short multimode optical fiber through axial dislocation welding. The CCD camera is connected with the dislocation welding multimode optical fiber; and the computer is connected with the CCD camera and is used for processing the speckle pattern acquired by the CCD camera. The device is small in size, and the stability, the anti-interference performance and the resolution ratio of a measurement system can be effectively improved.

This utility model discloses a broadband high-speed photodetector module, including: a housing and a driving circuit. The housing has an internal mounting cavity, a high-speed broadband response photodetector, and is fixed inside the housing via an SMA interface. An OLED display screen is embedded on the front of the housing and connected to the driving circuit via a flexible circuit board. The high-speed broadband response photodetector has a spectral response range of 800nm ​​to 1650nm, fully covering the wavelength requirements of multimode and single-mode optical fibers. It solves the limitations of traditional modules with single wavelength or narrow spectrum, significantly improves compatibility with different optical fiber systems, and is suitable for complex hybrid optical fiber network scenarios. Through the coordinated design of the cylindrical body on the side wall of the housing, the air outlet, and the heat dissipation components, the heat generated by the photodetector during operation can be quickly dissipated, avoiding performance degradation or device damage due to temperature rise, and ensuring long-term stable operation of the module under high-speed and high-load conditions.

This invention relates to the field of cable technology and discloses a safety early warning cable with temperature sensing. The cable includes a wrapping layer containing multiple insulated power wire cores, a protective layer outside the wrapping layer, a first vibration sensing element within the protective layer, and an isolation layer between the wrapping layer and the protective layer. By incorporating a spiral metal sheath within each conductor, with thermally conductive silicone grease filling the space between the sheath's inner wall and the temperature-sensing optical fiber, rapid and direct monitoring of the conductor's core temperature is achieved. Simultaneously, heat is transferred through the conductor's copper wires in the spiral microgrooves, the thermally conductive metal strip on the surface of the insulation layer, and the thermally conductive material in the filling layer to the multimode optical fiber core in the multi-core sensing cable, forming redundant temperature measurement channels. When the temperature of a conductor is abnormal, the corresponding temperature-sensing optical fiber and the multimode optical fiber core can be cross-verified, effectively avoiding false alarms caused by single-point faults or poor local contact, significantly improving temperature measurement reliability and response speed.

The application discloses a kind of broadband fiber spectrometer based on phase modulation, including polarization maintaining optical fiber, fiber collimator A, phase modulation device, fiber collimator B, multimode optical fiber, CCD image sensor and computer that are sequentially arranged, fiber collimator A is set to the light outlet of polarization maintaining optical fiber, phase modulation device carries out phase modulation to the incident light from fiber collimator A, fiber collimator B is set to the light inlet of multimode optical fiber, the light outlet of multimode optical fiber is aligned with CCD image sensor, and CCD image sensor is electrically connected with computer.The application uses the above structure to overcome the problem that spectrum resolution and measurement bandwidth are mutually restricted in fiber spectrometer.

A bend-insensitive multimode optical fiber attenuation test device and method includes a light source, a single-mode or few-mode injection pigtail, a coupling injection device, an optical power detector, and a beam quality analyzer. The light source is connected to the coupling injection device via the single-mode or few-mode injection pigtail, and the coupling injection device and the optical power detector are connected to the multimode optical fiber under test. The beam quality analyzer is connected to the multimode optical fiber under test via a bare fiber adapter. The test device provided by the present invention uses a high-precision five-dimensional adjustment frame to adjust the injection light angle and thus the injection light mode, achieving high flexibility in controlling the target mode during attenuation testing.

The corn fruit biological information detection device comprises a bottom plate, a waste liquid collection box and a U-shaped detection seat, a detection cavity is formed in an inner cavity of the U-shaped detection seat, a detection optical fiber is arranged on the inner wall of the detection cavity, and a light source, a spectrograph, a single-mode tail fiber and a multi-mode optical fiber are arranged at the two ends of the detection optical fiber respectively. Side frames are installed at the top ends of the outer walls of the two sides of the U-shaped detection base, a top beam is installed between the adjacent side frames, a controller and a flushing mechanism are arranged on the top beam, the flushing mechanism comprises a U-shaped walking frame, a spray head is installed at the bottom of the U-shaped walking frame, and two sets of tooth-shaped plugging plates are arranged at the bottom of the detection cavity; through the action of the light source, the single-mode tail fiber, the spectrograph, the multimode optical fiber and the detection optical fiber, rapid detection of corn fruit biological information is achieved, rapid washing of the detection cavity after detection is completed is achieved, the situation that residual corn fruit extracting solution affects the accuracy of next-time biological information detection is avoided, and the detection efficiency is improved.

The present invention discloses a wavelength-division multiplexing multi-user optical wireless communication system based on a spatial light modulator. Multi-wavelength signals from a transmitting end enter free space through a multimode optical fiber and a collimating lens, and after being expanded by an achromatic lens system, are irradiated on the spatial light modulator. After being modulated by the multi-wavelength hologram displayed on the spatial light modulator, optical signals of different wavelengths are split and deflected, and focused on corresponding receivers, realizing multi-channel signal transmission. The present invention solves the problem in traditional free-space optical communication that only point-to-point fixed transmission is supported, and multi-user and mobile users are not supported. Operations such as switching between users and multi-user power allocation can be performed, and it has the advantages of strong flexibility and easy deployment, and has good application prospects in free-space optical wireless communication systems.

The invention relates to an SMS structure Fabry-Perot ultrasonic sensor which comprises a packaging protection shell, a first single-mode fiber, a multimode fiber and a second single-mode fiber, the first single-mode fiber, the multimode fiber and the second single-mode fiber are sequentially arranged and welded, the welding area of the first single-mode fiber and the multimode fiber and the welding area of the second single-mode fiber and the multimode fiber form reflection end faces respectively, and a Fabry-Perot interference cavity is constructed. The cavity length of the Fabry-Perot interference cavity is the length of the multimode fiber; the packaging protection shell wraps the multimode fiber and the two welding areas and is connected to the first single-mode fiber and the second single-mode fiber. The packaging protective shell is provided with a sound transmission hole. A first single-mode fiber, a multi-mode fiber and a second single-mode fiber are sequentially arranged and welded to form a single-mode-multi-mode-single-mode (SMS) welding structure, a Fabry-Perot interference cavity is constructed by using the refractive index difference of a welding interface, the length of the multi-mode fiber is directly used as the cavity length, and the structure does not need to be additionally provided with a diaphragm or inscribe a grating through femtosecond laser.

Single-mode and multi-mode coaxial transceiver kilometer-level wireless optical communication devices belong to the field of wireless optical communication technology. Existing technologies fail to take into account both communication quality and communication distance under the premise of coaxial transceiver. The present invention is characterized in that a triple-clad optical fiber is arranged on the optical path between the optical antenna and the laser diode and photodiode; the triple-clad optical fiber is composed of a core, an inner cladding, a middle cladding and an outer cladding from the inside to the outside, and the middle cladding is doped with a laser working material and can generate laser light with the same wavelength as the communication light; at one end of the triple-clad optical fiber, the center is the core incident end face a, and the other two end faces are the inner cladding output end face b' and the middle cladding incident end face c, each made by the tapering technology; the end face of the other end of the triple-clad optical fiber is located at the back focus of the optical antenna; the laser diode light outlet and the core incident end face a are connected by a single-mode optical fiber; the inner cladding output end face b' and the photodiode light inlet are connected by a multi-mode optical fiber.

An example apparatus may include an optical splitter apparatus that includes a dual mode fiber having a single mode fiber core embedded in a multi-mode fiber core, a plurality of single mode fibers, and a funnel waveguide coupling the dual mode fiber to the single mode fibers. The optical splitter apparatus may be for use in a passive optical network. The single mode fiber core may be for transmitting downstream optical signals, where the funnel waveguide distributes the downstream optical signals to the single mode fibers. In addition, the single mode fibers may transmit upstream optical signals, and the funnel waveguide may direct the upstream optical signals into the multi-mode fiber core. The optical splitter apparatus may have an asymmetric insertion loss ratio between the downstream optical signals received via the single mode fiber core and the upstream optical signals received via the single mode fibers.

The optical fiber type light spot homogenizer comprises a machine frame, a laser source is arranged at one end of the machine frame, a multimode optical fiber corresponding to the laser source is arranged at the other end of the machine frame, the laser source emits a laser beam, the multimode optical fiber receives the laser beam, and the multimode optical fiber is connected with the machine frame. The multi-mode fiber laser is characterized in that the relative refractive index difference section of the inner side of the sunken inner cladding of the multi-mode fiber is in a two-stage step decreasing shape, and the center line of the laser beam and the center of the end face of the multi-mode fiber are aligned and offset in parallel by a section of radial offset. The device is small in size, low in cost, compact in structure, good in homogenization effect and stable in performance, and can be directly seamlessly integrated with an input laser source and an output optical fiber system. The optical fiber type light spot homogenizer assembly and the laser beam shaping system can achieve efficient light spot homogenization within the centimeter-level distance. The system can be applied to a vehicle-mounted laser radar, a vehicle-mounted head-up display, a multimode PON optical splitter, laser medical equipment or laser material processing equipment and the like.

The utility model relates to the field of optical fiber interference sensors, and discloses an M-Z interference sensor with a small excitation group velocity dispersion difference mode structure. Comprising a light injection single-mode optical fiber, a small-core-diameter step multimode optical fiber, a wide annular core optical fiber, an annular core optical fiber, a gradient refractive index multimode optical fiber, a large-core-diameter step multimode optical fiber and a light receiving single-mode optical fiber which are connected in sequence. The wide annular core optical fiber comprises a third quartz cladding and a third quartz fiber core, and the third quartz fiber core annularly wraps a third quartz layer; the annular core optical fiber comprises a fourth quartz inner wrapping layer, a fourth quartz fiber core and a fourth quartz outer wrapping layer, the fourth quartz inner wrapping layer is annularly wrapped by the fourth quartz fiber core, the fourth quartz fiber core is annularly wrapped by the fourth quartz outer wrapping layer, and the optical fiber radial refractive index distribution index of the gradient refractive index multimode optical fiber is 1.95-2. According to the scheme, the annular core optical fiber is used for injecting light to the gradient refractive index multimode optical fiber, two modes with smaller group velocity dispersion difference can be excited to interfere, and the sensitivity of the sensor is improved.

The invention relates to the technical field of wavelength division multiplexing passive optical network transmission optimization, in particular to a wavelength division multiplexing passive optical network transmission optimization method and system. Comprising the following steps: S1, constructing a network architecture through a plurality of pairs of wavelength stacked optical modules, dividing optical network units in the network architecture, and receiving and sending optical signals of a terminal through the optical network units; through the ONU architecture design of dense wavelength division multiplexing and transmitting-receiving separation, the capacity of a wavelength resource pool is further expanded, and in combination with the flexible branching ratio of 1: 8 to 1: 256 and the compatibility of single-mode and multi-mode optical fibers, it is ensured that the system can stably support 100 Gb / s total rate transmission under the scenes of different scales and different transmission distances; the problem that the wavelength resource utilization rate is low in a traditional static allocation mode is thoroughly solved.