27results about How to "Reduce nonlinear effects" patented technology

The present invention relates to the technical field of optical fiber devices, and proposes a hollow-core fiber power combiner, including an optical fiber bundle and a hollow-core optical fiber, wherein the optical fiber bundle is formed by taper-forming n solid-core optical fibers; the input end of the optical fiber bundle is the large end of the optical fiber bundle, and the output end of the optical fiber bundle is the small end of the optical fiber bundle, wherein one of the n solid-core optical fibers in the optical fiber bundle is located at the center as the central optical fiber, and the remaining n-1 optical fibers are distributed around the center optical fiber; the hollow-core optical fiber is a nested anti-resonant hollow-core optical fiber, which includes an outer cladding, a nested ring and a hollow-core region from the inside to the outside, and n-1 nested rings are distributed around the periphery of the hollow-core region; the laser of the input optical fiber bundle is input into the hollow-core optical fiber through the small end of the optical fiber bundle, and the long-distance transmission of the laser is realized by using the hollow-core optical fiber. The present invention has a simple and compact structure, high coupling efficiency, can better maintain the purity of the beam mode, and has great application value and potential advantages for high-power long-distance transmission of optical fiber lasers.

The invention relates to the technical field of coherent optical communication, in particular to a Dither signal generation and feedback acquisition circuit and method and a coherent optical module, and the circuit comprises an MCU and a DAC chip. The MCU comprises a disturbance generator, an SPI (Serial Peripheral Interface), an on-chip ADC (Analog to Digital Converter), an automatic bias controller and two DMA channels; the first DMA channel, the SPI interface and the DAC chip are connected in sequence, the disturbance generator is connected with the SPI interface, and the DAC chip is connected to a laser and used for sending Dither signals to the laser; the on-chip ADC is connected with the second DMA channel and the laser and used for collecting feedback signals under driving of the second DMA channel, and the on-chip ADC is sequentially connected with the automatic bias controller and the disturbance generator and used for sending optimized and adjusted Dither signal parameters to the disturbance generator. The running efficiency of the MCU can be improved, and the internal resource utilization rate of the MCU is also improved.

The invention discloses a continuous optical fiber laser, and relates to the technical field of lasers, the continuous optical fiber laser comprises an output device, a first stripper, a first beam combiner, a composite resonant cavity, a second beam combiner and a second stripper which are sequentially connected through a central fiber, the composite resonant cavity is internally provided with a plurality of sub-cavities, and the sub-cavities are used for filtering and enhancing laser beams; the continuous fiber laser further comprises a plurality of first pumping sources and a plurality of second pumping sources, wherein the plurality of first pumping sources are respectively connected with the first beam combiner; and the plurality of second pumping sources are respectively connected with the second beam combiner. According to the technical scheme, the overall structure is simple, and low-cost and high-efficiency suppression of the nonlinear effect is achieved only through cooperation of the output device, the stripper and the beam combiner.

The invention relates to the technical field of precision reducer testing, and discloses an angle measurement error suppression system and method in a precision reducer dynamic test, and the system comprises a servo motor closed-loop regulation and control module, a measurement shafting motion state monitoring module, a piezoelectric ceramic driver regulation and control module, and a combined control module. The method comprises the steps that first-step regulation and control are conducted through the servo motor closed-loop regulation and control module, second-step regulation and control are conducted through the piezoelectric ceramic driver regulation and control module, and according to the running states, monitored in real time, of the high-speed-end motor and the low-speed-end motor and the motion state, monitored in real time, of the measuring shaft system, and in combination with a preset standard, the high-speed-end motor and the low-speed- The control proportion of the closed-loop regulation and control module of the servo motor and the piezoelectric ceramic driver regulation and control module is dynamically adjusted, so that the dynamic angle measurement error is kept within the preset range, and the angle measurement error caused by the dynamic change of the system structure in the speed reducer testing process can be effectively reduced.

A laser transmission optical cable based on a hollow-core anti-resonance optical fiber is suitable for flexible transmission of ultrafast laser, and comprises an input laser beam, and a first optical window, a first air chamber, a first water chamber, a hollow-core capillary optical fiber, a hollow-core anti-resonance optical fiber, a second water chamber, a second air chamber and a second optical window which are sequentially arranged along the beam transmission direction, the hollow-core capillary optical fiber and the hollow-core anti-resonance optical fiber are glued to form a nested structure, and the ratio of the diameter of a cladding capillary of the hollow-core anti-resonance optical fiber to the diameter of a fiber core of the hollow-core anti-resonance optical fiber is 0.63-0.68. The hollow-core anti-resonance optical fiber has high single-mode purity, the problem that a laser mode is coupled to a high-order mode due to mechanical disturbance such as optical fiber bending and twisting can be solved, the hollow-core anti-resonance optical fiber has higher adaptability in a complex processing environment, the laser processing efficiency and stability are improved, and the optical fiber is suitable for large-scale production. And meanwhile, the influence of a heat effect under high power and a nonlinear effect caused by air in an ultrafast laser transmission process are considered.

The invention relates to a bending-resistant all-solid-state microstructure optical fiber. The bending-resistant all-solid-state microstructure optical fiber comprises a fiber core region and an inner cladding, the fiber core area comprises a first filling round hole, a first annular fiber core and a first groove ring; the first filling circular hole is located in the center of the fiber core area and has a first refractive index. The first annular fiber core wraps the first filling round hole and has a second refractive index; the first groove ring wraps the first annular fiber core and has a third refractive index; the inner cladding wraps the fiber core area and has a fourth refractive index; a plurality of second filling circular holes are distributed in the inner cladding, and the second filling circular holes have a fifth refractive index; the first refractive index is higher than the second refractive index; the second refractive index is higher than the fourth refractive index; the fourth refractive index is higher than the third refractive index; the third refractive index is higher than the fifth refractive index. According to the invention, the technical problem of poor bending resistance on the premise of large-mode-field transmission in the prior art can be solved.

The present disclosure belongs to the field of signal processing technology, and provides a weak current signal filtering method, system, electronic device and storage medium, the method comprising: dividing the noise into environmental noise, system noise and random noise according to the source of the noise; constructing a system noise model and an environmental noise model according to the environmental noise and the system noise; performing parameter compensation on the environmental noise and the system noise according to the system noise model and the environmental noise model to obtain a compensation value containing the random noise; filtering the random noise in the compensation value to obtain a filtering value of the current transmission signal. The step of selecting the filtering algorithm is removed, and different noise models are constructed according to different noise environments to adapt to different noise environments, thereby improving the filtering effect of the noise.

The application discloses an oil film damper damping structure, which comprises a bearing, a support seat and an adjusting structure, wherein the bearing comprises a bearing outer ring and a bearing inner ring, the bearing inner ring is suitable for being connected with a rotor; the inner ring of the support seat is coaxially arranged with the bearing outer ring to enclose an oil film cavity suitable for containing lubricating oil; the adjusting structure is fixedly arranged in the oil film cavity, and the adjusting structure is fixed on the bearing outer ring or the inner ring of the support seat; the adjusting structure comprises a flow control part, the flow control part comprises a streamlined surface and a flow resistance plane which are connected with each other, and the streamlined surface and the flow resistance plane are used for controlling the flow speed of the lubricating oil; the friction coefficient of the flow resistance plane is greater than that of the streamlined surface. The structure plays a damping role under the action of the friction resistance and the pressure difference resistance of the lubricating oil on the adjusting structure, the control effect of the oil film extrusion flow is strengthened, and the use and application range of the extrusion oil film damper are increased.

The invention belongs to the technical field of fiber lasers, and discloses a cladding fiber grating which comprises a cladding area and a fiber core area, and the cladding area is inscribed to form a cladding grating of a periodic structure. The cladding fiber bragg grating is adopted, residual pump light which is not absorbed in the fiber laser is reflected back to the gain fiber to be absorbed again, the length of the gain fiber in the fiber laser can be shortened to 30%-50% of the length of the gain fiber in a traditional scheme, and the cost of the fiber laser is reduced; meanwhile, the gain optical fiber with the short length can effectively reduce accumulation of the nonlinear effect, and laser output with higher power can be achieved.

The invention relates to the technical field of optical communication, in particular to a silicon optical chip, an external cavity laser and a method for restraining a micro-ring nonlinear effect. The P-doped region and the N-doped region at the two sides of the micro-ring resonant waveguide are respectively connected with the ground and an input voltage through an electrical connection module, so that a transverse electric field is formed in the micro-ring resonant waveguide, and free carriers generated after light passes through the micro-ring resonant waveguide are removed through the transverse electric field; and on the other hand, the P-doped region and the N-doped region are respectively connected with an external input voltage and the ground through the electrical connection module, so that bias voltage control on the two sides of the micro-ring resonant waveguide can be realized on the basis of not increasing redundant pins, free carriers generated in the micro-ring resonant cavity are eliminated, and the reliability of the micro-ring resonant cavity is improved. Therefore, the nonlinear effect of the micro-ring resonant cavity is effectively suppressed, and the micro-ring resonant cavity has the advantages of being simple in structure and meeting the miniaturization requirement.

The embodiment of the invention provides an elastic wave device and an electronic product. The elastic wave device comprises a piezoelectric layer; the IDT electrode layer is arranged on the piezoelectric layer, the IDT electrode layer comprises a first bus bar and a second bus bar which are oppositely arranged along a first direction, and a part between the first bus bar and the second bus bar is defined as an interdigital region; the electrode fingers are arranged in the interdigital area, the electrode fingers comprise a plurality of first electrode fingers and a plurality of second electrode fingers which are arranged at intervals in the second direction, first intervals are formed between the first electrode fingers and the second bus bars, and first intervals are formed between the second electrode fingers and the first bus bars; the interdigital area comprises a central area and additional film areas, the two edges of the central area in the first direction do not exceed the edges of the sides, away from the bus bar, of the first electrode fingers and the second electrode fingers, and the additional film areas are arranged on the two sides of the central area; and the additional film is arranged on the piezoelectric substrate, the additional film is arranged in the additional film area, and the material of the additional film is silicon dioxide, silicon oxide, silicon nitride, HfO2, silicon, resin, PI or titanium oxide.

The present invention discloses a linearized PGC demodulation signal processing method based on hybrid phase modulation. On the basis of sinusoidal phase modulation, triangular phase modulation is introduced to perform hybrid modulation on the laser phase modulation interferometer to obtain interference signals, which are then mixed with the carrier signal and its second-order harmonic signal to obtain a pair of phase quadrature signals; synchronous differential cross-multiplication and inverse tangent processing are performed on the quadrature signals to obtain phase signals that change with triangular phase modulation, and the demodulation phase is linearly corrected in real time using the obtained demodulation π integer phase without nonlinear error and the corresponding demodulation phase, and the demodulation nonlinear error is directly corrected by combining the π integer phase and the corrected demodulation phase. The present invention eliminates the influence of periodic nonlinear errors caused by phase modulation depth drift and carrier phase delay through linearized phase demodulation, and realizes high-precision phase demodulation.

This invention discloses a graded-index non-zero dispersion-shifted optical fiber based on orbital angular momentum modes, comprising an optical fiber body including a ring core and an optical fiber cladding surrounding the ring core. The optical fiber cladding includes a circular region inside the ring core and an outer optical fiber cladding outside the ring core. This invention aims to provide a feasible optical fiber structure for suppressing four-wave mixing to meet the requirements of low-dispersion transmission of multiple orbital angular momentum modes.

This invention discloses a submarine cable acoustic monitoring system based on scattering-type fiber optic fingerprint technology, belonging to the field of fiber optic sensing technology. The system includes a light source module, a transmitting module, a submarine cable fiber optic sensing unit, a dual-balanced detector module, and a signal processing module. In the light source module, the continuous light output from the laser is split into a probe light and a local reference light by a dynamic beam splitter. The probe light is modulated and injected into the submarine cable fiber, and the resulting backscattered Rayleigh light carries acoustic information back. The dual-balanced detector module has a built-in light intensity monitoring unit that monitors the light intensity of the reference light and the scattered light in real time. By comparing the two intensities, it sends a feedback control signal to the dynamic beam splitter, dynamically adjusting the splitting ratio to maximize the interference term intensity coefficient, thereby improving the signal amplitude and sensing sensitivity. This invention solves the problems of limited sensing distance and high laser linewidth requirements in traditional systems, and is suitable for long-distance, high-reliability submarine cable acoustic event monitoring and location in deep-sea environments.

The utility model discloses a kind of annular light beam laser beam combiner based on spindling annular optical fiber, annular light beam laser beam combiner uses (N+1)*1 combiner, the input end of annular light beam laser beam combiner includes a center optical fiber and N root side fiber, and the output fiber of annular light beam laser beam combiner is 1 spindling annular optical fiber.

The present invention discloses a high-precision MOEMS relative gravimeter based on a self-traceable grating, which belongs to the field of detection instruments, and includes a MEMS resonator, a self-traceable grating interferometer and a data processing module, wherein the MEMS resonator includes a folding beam, a fixed frame and a mass block, wherein both ends of the folding beam are connected to the inner side wall of the fixed frame, and the mass block is suspended in the center of the fixed frame through the support of the folding beam, and the self-traceable grating interferometer includes a self-traceable grating and an interference measurement reading head, and the self-traceable grating is arranged on the mass block. The present invention adopts the above-mentioned high-precision MOEMS relative gravimeter based on a self-traceable grating, which has extremely high measurement accuracy, and the displacement measurement can be traced in real time. Compared with the traditional MOMES relative gravimeter, it can improve the accuracy of its displacement measurement and reduce the nonlinear effect of gravity acceleration measurement.

The utility model relates to an ultralow-loss single-mode optical fiber and an optical fiber product. The effective area lambda eff of the ultra-low-loss single-mode fiber is 130 microns < 2 >, and the ultra-low-loss single-mode fiber comprises a core layer, an inner cladding layer and an outer cladding layer. The inner wrapping layer wraps the periphery of the core layer and comprises a first wrapping layer and a second wrapping layer which are concentrically arranged in sequence from inside to outside in the radial direction; the outer cladding layer is coated outside the inner cladding layer and comprises a third cladding layer and a fourth cladding layer which are concentrically arranged in sequence from inside to outside along the radial direction; the single-mode optical fiber has a large mode field diameter and an effective area, and is good in transmission performance; the optical fiber is small in transmission loss and attenuation, is not sensitive to bending, can keep a low nonlinear effect while obtaining a high optical signal-to-noise ratio, is easy to produce, and is suitable for an optical fiber communication system with higher speed and higher capacity.

The present invention relates to the field of permanent magnet synchronous motor current control, and specifically to a permanent magnet synchronous motor current loop control method and device based on cascade sliding mode resonance. The method and device first construct a permanent magnet synchronous motor mathematical model, and the nonlinear influence of the inverter is taken into account during the construction of the permanent magnet synchronous motor mathematical model; then construct a cascade sliding mode resonance controller, and the cascade sliding mode resonance controller designs a super spiral sliding mode control law based on high-order sliding mode theory during the construction; finally, a fixed time adaptive estimation law is designed in the cascade sliding mode resonance controller to estimate unknown disturbances, and a cascade sliding mode resonance control structure combining a super spiral controller and a resonance controller is formed to achieve the purpose of suppressing current loop harmonics and ensuring good robustness of the control system, realize the rapidity and robustness of the current loop response, and reduce the distortion of the output current of the permanent magnet synchronous motor, and effectively improve the control accuracy under the condition of motor system parameter changes.

The utility model provides a kind of continuous fiber laser, it is related to laser technical field.Fiber laser includes few-mode laser oscillation cavity, pump source mode filter and first cladding light filter;Pump source injects pump light to few-mode laser oscillation cavity;Few-mode laser oscillation cavity converts received pump light into signal light, and output to mode filter, mode filter filters high-order mode in signal light into optical fiber cladding, and fiber core is only for single fundamental mode signal light to pass;First cladding light filter peels high-order mode light and residual pump light.The utility model provides fiber laser, by few-mode laser oscillation cavity, reverse pump light is converted into signal light, and signal light is transmitted to mode filter, mode filter can filter out high-order mode in signal light except fundamental mode, realize single-mode laser output, and first cladding light filter is set in the output end of fiber laser, can guarantee that only fundamental mode is included in signal light output by fiber laser.

The invention discloses a picosecond pulse optical fiber amplifier and a laser, and relates to the technical field of optical fiber laser amplification. The picosecond pulse optical fiber amplifier comprises a polarization-maintaining optical fiber picosecond mode-locked oscillator, a first optical fiber circulator, a first polarization-maintaining optical fiber polarization beam splitter, an optical fiber Faraday rotation structure, an optical fiber grating, a second polarization-maintaining optical fiber polarization beam splitter and a second optical fiber circulator which are sequentially connected through optical fibers, and the amplification frequency modulation assembly is respectively connected with the first optical fiber circulator and the second optical fiber circulator through optical fibers. Therefore, the picosecond pulse optical fiber amplifier enables the signal light to be separated from the stray light transmitted from the fiber bragg grating by controlling the polarization state of the laser, the pulse broadening and compression of the laser can be completed only through one fiber bragg grating, and the nonlinear effect generated in the pulse amplification process is reduced. Therefore, high-energy pulses equivalent to input signal light pulse width are obtained in an all-fiber structure, the structure is simple, and integration is easy.

The invention relates to a commercial vehicle steering wheel NVH transfer function test method and device and a storage medium. The method comprises the following steps: determining a target structure having a nonlinear influence on a transfer function in a commercial vehicle steering system, and preprocessing the target structure to eliminate the nonlinear influence of the target structure on the transfer function when a steering wheel transfer function test is carried out; the method comprises the following steps of: testing a transfer function of a steering wheel of a steering system: arranging an acceleration sensor on the steering wheel of a vehicle which is preset according to conditions; vibration excitation source parameters are set, vibration excitation is carried out, acceleration sensor signals are used as output, and vibration excitation signals are used as input; in the transfer function fitting process, Fourier transform is carried out on input and output signals, time domain signals are converted into frequency domain signals, cross spectrum of the input and output signals is calculated, self spectrum of the input signals is calculated, frequency response function is calculated by using the cross spectrum and the self spectrum, and the transfer function is fitted through a least square method; and acquiring the NVH property of the steering wheel of the commercial vehicle based on the transfer function.

The invention discloses an ytterbium-doped optical fiber mode-locked laser. The ytterbium-doped optical fiber mode-locked laser comprises a first pumping source, a first regenerator, a second pumping source and a second regenerator, wherein the first regenerator comprises a first ytterbium-doped optical fiber and a pulse broadening device, and the second regenerator comprises an isolator, a pulse compression device, a frequency spectrum broadening optical fiber and a band-pass filter; the design of a staggered band-pass filter is realized through two regenerators, spectrum broadening caused by a self-phase modulation effect is realized, and mode-locked pulse output can be realized through energy input of a first pumping source and a second pumping source; the peak power is reduced by broadening the pulse so as to reduce the nonlinear effect, the high-energy output pulse is generated in the optical fiber mode-locked laser, meanwhile, the central wavelength interval between the pulse broadening device and the band-pass filter can effectively prevent noise and continuous component oscillation starting, and the pulse quality is improved.

This invention relates to a large effective area ultra-low attenuation multi-core optical fiber and its applications. The large effective area ultra-low attenuation multi-core optical fiber includes at least four core layers and a common cladding surrounding and covering the core layers. The core layers are symmetrically and uniformly distributed across the fiber cross-section. Each core layer is surrounded by an inner cladding and a recessed inner cladding layer, arranged sequentially from the inside to the outside. The common cladding layer includes a first outer cladding layer and a second outer cladding layer. The relative refractive index difference between the first and second outer cladding layers increases from the inside to the outside. This invention, through a multi-layer cladding structure of "inner cladding-recessed inner cladding-first outer cladding-second outer cladding layer," combined with the increasing relative refractive index difference between the first and second outer cladding layers from the inside to the outside, achieves a synergistic improvement in ultra-low attenuation, large effective area, ultra-low inter-core crosstalk, excellent bending resistance, and good system compatibility, providing an ideal transmission medium for long-distance, high-capacity space-division multiplexing optical communication systems.

The present invention relates to the field of antenna technology, and discloses a liquid metal reconfigurable antenna and an antenna array. The liquid metal reconfigurable antenna comprises a first antenna tube and a second antenna tube that are interconnected, and a piston and a piston rod are arranged in each antenna tube. The piston rod can drive the piston to move along the axial direction of the antenna tube, and the first antenna tube and the second antenna tube are filled with liquid metal. The present invention drives the piston to move along the axial direction of the antenna tube by moving the piston rod, changes the liquid level of the liquid metal in the first antenna tube and the second antenna tube, and realizes the continuous reconstruction of the reconfigurable antenna shape. At the same time, the cross-sectional area of ​​the second antenna tube is larger than the cross-sectional area of ​​the first antenna tube, so the liquid level of the first antenna tube changes more significantly, and the antenna shape can be precisely controlled, which greatly broadens the working frequency band of the antenna. The reconfigurable antenna is sealed at both ends to avoid leakage of liquid metal when tilted, and increase environmental adaptability.

The application discloses an anti-resonant fiber optimization design method and system for infrared waveband transmission, and belongs to the technical field of optical fiber communication, and comprises the following steps: constructing an air-core anti-resonant fiber model for cooperatively optimizing limited loss and bending loss in a target infrared waveband, wherein the air-core anti-resonant fiber model has a five-tube nested structure; selecting a group of key structure parameters to be optimized; determining the theoretical value range of the large-circle wall thickness and the small-circle wall thickness based on the anti-resonant optical principle, and combining with the preparation process constraint to determine the common feasible domain of all the key structure parameters; and cooperatively optimizing through phased parameterization scanning, wherein the optimization parameter subspace is determined through coarse scanning, and the optimal structure parameter combination meeting the preset loss threshold is screened out in the subspace through fine scanning. According to the application, the fiber structure parameters are cooperatively optimized in the 808 nm waveband, the limited loss and the bending loss are significantly reduced, and good process feasibility is ensured.

The application discloses a kind of denitration facility intelligent management and control method and system, wherein denitration facility intelligent management and control method includes the following steps: carrying out online monitoring of catalyst performance;After completing online monitoring of catalyst performance, the online monitoring of regulating valve operating characteristic is carried out, and self-correction processing is carried out;After completing online monitoring of regulating valve operating characteristic and carrying out self-correction processing, the online monitoring and early warning of air preheater pressure difference are carried out;After completing online monitoring and early warning of air preheater pressure difference, denitration facility ammonia escape and NOx Intelligent collaborative management and control are carried out.The application calculates catalyst reaction rate constant, activation energy and pre-exponential factor in real time, fits attenuation curve and predicts remaining life, changes the defect that traditional offline detection lag, cannot cover wide working condition, realizes active predictive maintenance.

The invention discloses a whole vehicle vibration noise transfer function test device and test method. The testing device comprises a vibration exciter used for exciting a vehicle tire tread; the receiver is used for picking up vehicle vibration data and sound data; and the control acquisition system is electrically connected with the vibration exciter and the receiver. The control acquisition system controls the vibration exciter to input a periodic random signal to the tread and synchronously acquires an input signal of the vibration exciter and a response signal of the receiver; and controlling the acquisition system to process to obtain a cross-power spectrum of the input signal and the response signal and an auto-power spectrum of the response signal, and calculating a transfer function. The testing method comprises the following steps: inputting a periodic random signal to a tread, and picking up a vibration / noise response signal in a vehicle; an input signal and a response signal of a receiver are synchronously collected and processed to obtain a cross-power spectrum of the input signal and the response signal and an auto-power spectrum of the response signal, and a transfer function is calculated. According to the invention, the tire tread can be excited, the transfer function can be obtained, and the test result is accurate and reliable.