184 results about "Dispersion compensation" patented technology

The invention provides an underground structure boundary identification method and system based on distributed optical fiber sensing, and relates to the technical field of underground structure detection and boundary identification. The method comprises the following steps: firstly, arranging a sensing array in a to-be-detected area, establishing a channel corresponding to a space coordinate, and collecting a non-excitation base line; medium and noise are estimated through low-energy probe, excitation frequency band, energy and repetition rate are optimized, and the signals are emitted by an adaptive seismic source; reflection and transmission responses are synchronously collected under the unified time reference; performing wavelet denoising, temperature and dispersion compensation and time alignment on the data, and extracting amplitude, phase and frequency characteristics; gradient is calculated on the feature field, non-maximum suppression is carried out, and stable boundary points are obtained by adopting self-adaptive double thresholds based on local statistics and combining time continuity and space connectivity constraints; a two-dimensional section is obtained through spline fitting, a three-dimensional model is reconstructed under the constraint of multi-section consistency, a section map and the three-dimensional model are output, and high-precision, real-time and visual detection of small-size boundaries is achieved.

The invention belongs to the technical field of distributed optical fiber sensing and low-altitude security and protection, and particularly relates to an unmanned aerial vehicle long-distance tracking method based on distributed optical fiber vibration sensing. The invention relates to an unmanned aerial vehicle vibration / electromagnetic fusion multi-mode identification method, a special installation formation design, a dispersion compensation and amplitude phase error compensation design, an unmanned aerial vehicle target vibration / electromagnetic fusion multi-mode identification design, a detection capability calculation method of an unmanned aerial vehicle vibration sound pressure-space attenuation law-distributed optical fiber processing equipment detection capability coupling model, a long-distance sensing optical cable and an electromagnetic monitoring node. According to the tracking method, a special optical fiber installation mode, dispersion compensation and phase error compensation of an original phase signal, a vibration / electromagnetic fusion multi-mode identification method, an unmanned aerial vehicle vibration sound pressure-space attenuation model-distributed optical fiber processing equipment detection capability corresponding method and other innovative work are adopted; a mature distributed optical fiber vibration sensing system is utilized to realize long-distance passive detection and target tracking of the low-slow-small unmanned aerial vehicle.

The invention discloses an optical fiber signal transmission system and method based on quantum noise encryption, and relates to the technical field of optical fiber communication, and the system comprises a composite modulation transmitting module, a dispersion compensation relay module, a coherent receiving module and a digital signal processor. The composite modulation transmitting module comprises an electro-optical modulator and a quantum noise randomization encoder; the dispersion compensation relay module comprises an adjustable dispersion compensator and a Raman amplifier; the coherent receiving module comprises a local oscillator laser and a 90-degree optical mixer; a digital signal processor includes a clock recovery unit and a maximum likelihood sequence detector. All the modules are sequentially connected and cooperatively work. And the adjustable dispersion compensator dynamically applies reverse dispersion compensation calculated based on a dispersion coefficient and a transmission distance according to the dispersion amount monitored in real time. According to the invention, through technologies of quantum noise encryption, dynamic dispersion compensation, Raman amplification, coherent reception and the like, safe and efficient transmission with single-wave 400Gbps and 100km transmission bit error rate less than or equal to 1 * 10 <-12 > is realized.

The invention discloses an ultra-wideband femtosecond optical parametric oscillator capable of being quickly tuned, and relates to the technical field of optical parametric oscillators. The oscillator comprises a frequency doubling device, an optical parametric oscillator resonant cavity device and a dispersion compensation chirp mirror pair module. According to the invention, the original phase matching bandwidth is further broken through by adopting a non-collinear phase matching mode that the transmission included angle between the pump light and the signal light is 2.5 degrees, and rapid wavelength tuning can be realized only by finely tuning the cavity length under the condition that the angle of the nonlinear crystal is not adjusted; the broadband tunable optical parametric oscillator can break through the bottlenecks in the aspects of wavelength tuning range, wavelength tuning speed and the like of the existing near-infrared optical parametric oscillator, and provides a novel light source with larger wavelength tuning range and higher tuning speed for the fields needing broadband tunable light sources, such as spectroscopy, micro-nano processing, optical frequency combs and the like.

The invention belongs to the technical field of microwave photon links, and particularly relates to a high-resolution microwave photon frequency measurement system based on real-time Fourier transform. The link comprises a mode-locked laser, a first dispersion compensation module, a second dispersion compensation module, a dual-drive Mach-Zehnder modulator, a Mach-Zehnder modulator, a dispersion optical fiber, a time lens, an erbium-doped optical fiber amplifier, a photoelectric detector and an oscilloscope; the mode-locked laser outputs femtosecond Gaussian light pulses, and the femtosecond Gaussian light pulses are injected into the first dispersion compensation module and then stretched into chirp light pulses; modulating the chirp light pulse through electro-optical modulators which are connected in parallel; the modulated optical signal is subjected to time amplification processing through a dispersion optical fiber, a time lens, a second dispersion compensation module and an erbium-doped optical fiber amplifier in sequence; and the optical signal after time amplification processing is converted into a microwave pulse carrying frequency information of the signal to be detected by a photoelectric detector, and the microwave pulse is observed by an oscilloscope.

The invention discloses a terahertz phased array secondary sub-array sub-band dispersion compensation design method. The method comprises the following steps: step 1, constructing a terahertz phased array system primary sub-array unit and a sub-band bandwidth; step 2, constructing a quadratic subarray and sub-band decision variable constraint condition; step 3, constructing a quadratic subarray and a digital sub-band decision variable group; 4, phased array beam quality optimization target parameters are determined according to terahertz phased array application requirements; step 5, carrying out joint optimization solution on the secondary sub-array and the sub-banding topological structure; and step 6, optimal phase compensation parameter set calculation and compensation processing are carried out. Compared with the existing uniform division or single compensation mode, the subarray and the subband are smaller in scale, the spatial three-dimensional layout is easier to realize, the time dispersion and the spatial dispersion of the broadband large-scale terahertz phased array system are eliminated to a certain extent, and the accurate high-quality direction of the terahertz wave beam is realized.

The invention belongs to the technical field of temperature demodulation, and particularly relates to a temperature measurement method and device based on machine learning and a storage medium, and the method comprises the steps: converting the temperature change into the wavelength shift of an interference spectrum through an interference type optical fiber temperature sensor; performing time domain stretching on the wavelength offset by using the dispersion compensation optical fiber to obtain time sequence offset; the method comprises the following steps: acquiring time sequence offset through signal acquisition equipment to obtain time domain sequence data, and preprocessing the time domain sequence data; position coding is adopted to obtain a feature sequence containing time sequence information; inputting the feature sequence into a Transform neural network to extract global features; normalizing the global features and then enhancing the global features; and mapping the enhanced features through a full connection layer of the Transform neural network, and outputting a predicted temperature value. And high-speed and high-precision temperature prediction is realized.

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

The application provides a communication device, a base station and a communication system. The communication device comprises a power divider, a coupler group and a multiplexer connected in sequence. The power divider is connected with the coupler group through at least two first lines. The power divider can divide light into at least two light beams. Each light beam is transmitted to the coupler group through a first line. Transmission of any two light beams in the corresponding first line has a phase difference and a time difference. The coupler group couples and interferes the received at least two light beams, and outputs at least two coupled light beams. Each coupled light beam enters the multiplexer through a second line. Transmission of any two coupled light beams in the corresponding second line has a time difference. The multiplexer can orthogonally combine the received coupled light beams. The communication device can perform dispersion compensation on the light to suppress pulse broadening, thereby reducing the bit error rate of optical signal transmission and reducing the power loss of the optical signal.

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

In one embodiment, an optical transceiver includes a digital signal processor, a transmitter coupled to the digital signal processor, and a receiver coupled to the digital signal processor. The receiver is configured to receive an optical signal. The receiver includes a demultiplexer for optical demultiplexing of the optical signal into a plurality of channels, and a plurality of dispersion management devices. Each of the dispersion management devices is associated with a respective channel of the plurality of channels of the demultiplexer and is configured for dispersion compensation at the respective channel. Each of the dispersion management devices includes a thermal control component configured to thermally adjust the dispersion compensation by the dispersion management device based on an output of the digital signal processor.

The invention relates to the technical field of digital-to-analog conversion, in particular to a large-dispersion compact chirped pulse time domain compression method, which comprises the following steps of: projecting a broadened chirped pulse to a first grating in an inclined incidence mode, and moving adjacent back and forth diffraction spots point by point in a direction parallel to a grating scribed line; the first grating and the second grating are oppositely arranged in parallel to form a double-grating group; controlling the chirped pulse to perform multiple back-and-forth diffraction between the first grating and the second grating to obtain a preset large dispersion amount; an angular dispersion steering module is arranged on a back-and-forth diffraction light path of the chirped pulse, and vertical angular dispersion introduced due to oblique incidence is turned into horizontal angular dispersion. An angular dispersion compensation module is arranged on a light path before the chirped pulse is output, and the angular dispersion accumulated by multiple back-and-forth diffraction is offset and compensated. According to the method, on one hand, the dispersion amount several times that of a traditional pulse time domain compressor can be obtained, on the other hand, the compact design of the structure of the compressor can be achieved, and the method has important engineering application value.

The application belongs to the technical field of temperature demodulation, and particularly relates to a temperature measuring method and device based on machine learning and a storage medium, the method comprising: converting temperature changes into wavelength shifts of an interference spectrum by an interference optical fiber temperature sensor; stretching the wavelength shifts in the time domain by using a dispersion compensation optical fiber to obtain time sequence shifts; collecting the time sequence shifts by a signal acquisition device to obtain time domain sequence data, and preprocessing the time domain sequence data; obtaining a feature sequence containing time sequence information by using position coding; inputting the feature sequence into a Transform neural network to extract global features; enhancing the global features after normalization; and mapping the enhanced features by a full connection layer of the Transform neural network to output a predicted temperature value. High-speed and high-precision temperature prediction is realized.

The present invention discloses a pump light source for generating high-fidelity tensor network states, comprising: a pump laser system, an optical loop system, a polarization adjustment system, and a dispersion compensation system. The pump laser system generates pump laser pulses; the optical loop system periodically pumps a tensor network state generator with the pump laser pulses; the polarization adjustment system regulates the polarization of the pump laser pulses each time they pass through the tensor network state generator; and the dispersion compensation system compensates for the group velocity dispersion generated when the pump laser pulses circulate in the optical loop system. The pulse light source generated by this scheme exhibits stable relative phases between pulses. As a pump light source for an optical tensor network state generator, it can generate high-fidelity tensor network states.

A wavelength dispersion compensation device (6) comprises: a wavelength dispersion compensation unit (61) that, on the basis of a set wavelength dispersion compensation amount, compensates for the difference in wavelength dispersion of a reference interference signal with respect to a measurement interference signal; and a wavelength dispersion amount adjustment unit (62) that, on the basis of a compensation index corresponding to the difference in wavelength dispersion between the reference interference signal and the measurement interference signal, adjusts the wavelength dispersion compensation amount set in the wavelength dispersion compensation unit 61.

The invention discloses a disc Mmyshev mode-locked laser, and belongs to the technical field of ultrafast laser. The disc Mmyshev mode-locked laser comprises a laser gain module, a first nonlinear medium, a second nonlinear medium, a first interference filter, a second interference filter, a dispersion compensation module, an output coupling mirror, a first concave reflecting mirror, a second concave reflecting mirror, a high reflecting mirror, a third concave reflecting mirror and a fourth concave reflecting mirror. According to the disc Mmyshev mode-locked laser, a Mmyshev filtering mechanism is introduced into the disc Mmyshev mode-locked laser, and mode-locked self-starting and ultra-short pulse output under the condition of high average power are achieved. The disc Mmyshev mode-locked laser does not need an SESAM or Kerr mode-locked medium, can obtain stable ultrashort pulses smaller than 100 femtoseconds, has high stability, self-starting, good beam quality and structural expandability, and is suitable for application fields such as precise micromachining and extreme ultraviolet lithography driving sources.

This invention discloses an infrasound localization method for minor pipeline leaks, comprising: acquiring the original infrasound signal of the pipeline leak; performing variational mode decomposition on the original infrasound signal to obtain IMF components; based on the IMF components, using an improved generalized cross-correlation function to obtain the time difference between the infrasound reflection to the upstream and downstream ends of the pipeline; calculating the wave velocity of the infrasound according to the pipeline characteristics; and determining the location of the pipeline leak point based on the time difference and wave velocity. The improved generalized cross-correlation function method involves: constructing an analytical signal based on the IMF components; using an improved linear adaptive weighted local approximation algorithm to obtain the local optimal solution of the IMF components; and performing inverse attenuation dispersion compensation analysis based on the generalized cross-correlation function to obtain the time difference between the infrasound reflection to the upstream and downstream ends of the pipeline. This invention can accurately locate the pipeline leak point.

The invention discloses an automatic configuration method for optical path subsystem design, and relates to the technical field of optical communication transmission, and the method comprises the steps: inputting configuration parameters required by an optical path subsystem to be designed, and summarizing and outputting a first configuration table which comprises the optical cable lengths, average attenuation, optical cable types, protection modes and transmission rates of all optical path sections; data resource analysis is carried out on the table based on the AI learning technology, and an optical path configuration scheme of optical amplification board card combination and dispersion compensation under different transmission rates is given; and performing multi-layer verification on the optical path configuration scheme, and outputting an optimal configuration scheme. According to the method, on the basis of the AI calculation and automation technology, corresponding configuration is provided for different optical path conditions under the condition that a machine continuously learns configuration, and the four technical values of efficiency improvement, accuracy controllability, cost optimization and standard unification are achieved.

The present application discloses a fiber optic sensor and a measurement method, apparatus, and storage medium. By performing, based on the microwave signal, intensity modulation on the optical signal, then inputting the modulated optical signal into the fiber optic containing the weak reflection grating array, a reflected signal is obtained. Thereafter by performing dispersion compensation on the amplified partial reflected signal, and based on the dispersion-compensated reflected signal and the non-dispersion-compensated reflected signal, the change amounts respectively corresponding to positions in the fiber optic containing the weak reflection grating array are determined.

In one embodiment, a method for dispersion compensation by an optical transceiver includes: receiving an output from a digital signal processor of the optical transceiver; determining a difference between the received output and an initial target output; based on determining that the difference between the received output and the initial target output exceeds a threshold, tuning a temperature of a dispersion management device of the optical transceiver across a first temperature range; identifying an adjusted target output based on the temperature tuning across the first temperature range; and adjusting the temperature of the dispersion management device to an adjusted target temperature corresponding to the adjusted target output.

The present disclosure provides a communication radar integrated optical fiber remote system and a phase locking method. A remote antenna unit is configured to receive a reflected microwave signal, and modulate the amplitude of the microwave signal to obtain an initial optical carrier signal. A dispersion compensation unit is connected with the remote antenna unit and configured to perform dispersion compensation on the initial optical carrier signal to obtain an optical carrier signal. A central unit is connected with the dispersion compensation unit and configured to perform phase locking using the received optical carrier signal to obtain an output optical signal. The frequency of the output optical signal is the same as that of the optical carrier signal, and the phase of the output optical signal is the same as that of the optical carrier signal. A signal output unit is connected with the central unit and configured to output the output optical signal. The present disclosure realizes the consistency of the frequency and the phase synchronization of the output optical signal and the optical carrier signal, realizes low phase noise carrier recovery, and improves the communication and radar performance.

The application relates to a full-polarization-maintaining fiber femtosecond laser based on a mode-locking starting promotion structure. The laser comprises a nonlinear amplification ring mirror with a double-path gain fiber, can realize continuous adjustment of a phase difference, introduces a nonlinear phase shift related to laser pulse intensity, reduces a mode-locking threshold of the nonlinear amplification ring mirror laser, improves self-starting mode-locking capability of the laser, and outputs high-power and high-stability ultrashort pulses; a non-reciprocal phase shift element introduces a linear phase shift bias for clockwise and counterclockwise propagation pulses; a linear arm introduces an optical element with a dispersion compensation function, ensures compactness of the oscillator, is used for outputting pulses, simultaneously provides seed pulse pre-chirp management for subsequent higher-power amplification, and realizes flat wide spectrum. The laser adopts a full-polarization-maintaining fiber structure, has good self-starting mode-locking characteristics, is beneficial to pulse filtering and shaping, and simultaneously has the advantages of compact structure, good stability, high damage threshold, high output power and low noise.

An off-axis single-grating multi-pass pulse compressor disclosed by the present invention comprises a compression module and at least one group of mirror groups, the mirror groups are used for increasing dispersion compensation of the compression module, and the compression module comprises a D-shaped reflector, a grating, a plane reflector, a first horizontal mirror and a first high-low mirror. Each group of mirror group comprises two mirrors, one mirror of each group of mirror group is located at the laser output end of the compression module, and the other mirror of each group of mirror group is located above the first high-low mirror, or the other mirror of each group of mirror group is located above the second high-low mirror. And the other mirror of each mirror group is positioned on one side of the first high-low mirror and has the same height with the horizontal plane. According to the off-axis single-grating multi-pass pulse compressor, a multi-pass single-grating compressor can be achieved, the total dispersion compensation amount is greatly increased, the advantages of low cost and small size of a transmission-type single-grating compressor can be reserved, and the compression requirement of ultra-large chirped pulses can be met.

The invention discloses an optical fiber nonlinear compensation method and device, equipment, a storage medium and a product. The method comprises the following steps: after carrier phase recovery and before forward error correction decoding are carried out on a signal transmitted by an optical fiber, DBP nonlinear compensation is carried out on the signal; wherein the signal is subjected to optical fiber dispersion compensation before clock synchronization, and the DBP nonlinear compensation comprises the following steps: adding optical fiber dispersion to simulate a reverse transmission condition, and performing segmented compensation on the optical fiber dispersion and nonlinearity based on SSFM. Due to the fact that the DBP nonlinear compensation is carried out after the carrier phase is recovered, the DBP nonlinear compensation can be carried out on the signals with the performance converged and stable, the accuracy and stability of compensation can be improved, in addition, single sampling of the signals after the carrier phase is recovered is recovered, and the complexity of the DBP nonlinear compensation can be effectively reduced.

An aspect of the present invention is an estimation device including: a control unit that estimates a vibration position that is a position on an optical fiber where vibration is induced by vibration of an external environment based on a reception signal that is a result of propagation of a transmission signal that is an optical signal transmitted by a transmitter through the optical fiber, in which the control unit executes estimation processing including: compensation processing including wavelength dispersion compensation processing of compensating for wavelength dispersion with respect to the reception signal, transmission signal estimation processing of estimating the transmission signal based on a result of the wavelength dispersion compensation processing, wavelength dispersion reapplication processing of reapplying the wavelength dispersion to a result of the compensation processing, and vibration position estimation processing of estimating the vibration position based on a result of inverse mapping of mapping according to the vibration position, the mapping representing a change in the transmission signal due to propagation through the optical fiber, acting on a result of the wavelength dispersion reapplication processing and a result of the transmission signal estimation processing.

The application relates to the field of optical information technology, and particularly relates to a high-energy thulium-doped fiber laser based on self-locking mode and dispersion management technology, wherein a pump laser is connected with one end of a pump protector, the other end of the pump protector is connected with an a end of a wavelength division multiplexer, a b end and a c end of the wavelength division multiplexer are respectively connected with an i end of a three-port circulator and one end of a thulium-doped gain fiber, the other end of the thulium-doped gain fiber is connected with a d end of an optical coupler, an e end of the optical coupler is connected with one end of a polarization controller, the other end of the polarization controller is connected with one end of a single-mode optical fiber, the other end of the single-mode optical fiber is connected with a g end of the three-port circulator, an h end of the three-port circulator is connected with one end of a collimator, and the other end of the collimator is provided with a dispersion compensation assembly, high-energy ultrashort pulses can be generated, the structure is optimized, and the manufacturing cost is reduced.

A method for monitoring a crystallizer in a high-temperature environment based on an improved BOCDA comprises the following steps: after a sensing optical fiber is laid on the surface of the crystallizer in a two-dimensional plane mode, the sensing optical fiber and the BOCDA arranged in a normal-temperature environment are respectively connected through a dispersion compensation optical fiber (DCF); the optical fiber Brillouin frequency shift (BFS) on a specific section distance in the sensing optical fiber is obtained by setting modulation frequency parameters, and then temperature information of the surface of the crystallizer is obtained through calculation. According to the invention, the sensing optical fiber with a heat-resistant coating layer is combined with the dispersion compensation optical fiber (DCF), and the BFS of the sensing optical fiber is remotely measured by utilizing the property that the BFS of the two optical fibers is greatly different, so that the accurate temperature measurement in a high-temperature environment is realized.

This disclosure generally relates to an optical coherence tomography (OCT) system. This disclosure particularly relates to an OCT system with a multi-pass dispersion compensation cell incorporated into its reference arm. This disclosure further relates to a hand-held compact OCT system suitable for inspection of an ear of a mammal.

Disclosed in the present application are a dispersion compensation device and a dispersion compensation method. The dispersion compensation device at least comprises a first compensation element and a second compensation element, wherein each compensation element comprises a refractive interface and a reflective interface. A light beam to be subjected to compensation propagates between the compensation elements in a normal-incidence / normal-exit propagation mode on the basis of the refractive interfaces, and the propagation direction and incidence and exit positions of said light beam within the compensation elements are changed on the basis of the reflective interfaces, such that said light beam exits from the at least two compensation elements after undergoing at least two rounds of reflection between the first compensation element and the second compensation element. In the dispersion compensation device provided in the present application, a normal-incidence / normal-exit mode is used such that a light beam to be subjected to compensation propagates between compensation elements without introducing dispersion, and multiple rounds of reflection are performed by means of a first compensation element and a second compensation element that are arranged opposite each other and staggered, thereby achieving a high degree of dispersion compensation on the basis of a relatively simple optical structure.

The invention relates to the technical field of optical fiber communication, and provides a carrier-free auxiliary signal phase reconstruction method and system based on a time domain symmetric architecture, and the method comprises the steps: constructing a symmetric dispersion compensation FIR filter based on a symmetric time domain impulse response function in a dispersion transfer function; acquiring the time domain amplitude of the to-be-measured optical signal and the time domain amplitude of the dispersion light signal; embedding the symmetric dispersion compensation FIR filter into a GS iterative algorithm, and reconstructing the phase based on the time domain amplitude of the optical signal to be measured and the time domain amplitude of the dispersion light signal to obtain a reconstruction result; wherein in each iteration process, dispersion compensation is carried out on the optical signal time domain amplitude of the current iteration through a symmetric dispersion compensation FIR filter; and performing fixed-point quantitative processing on the coefficients of the symmetric dispersion compensation FIR filter in the dispersion compensation calculation process, and merging the same coefficient items in the coefficients. Compared with the prior art, the calculation complexity of phase reconstruction is reduced.