228 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.

Chromatic dispersion compensation is performed in one or more pluggable optical transceiver (POT) devices operating within an intensity-modulated direct-detection (IMDD) optical network. Compensation is performed within each POT using an electrical and / or optical chromatic dispersion module which are controlled by a set of parameters. A network computing device includes a computer processor and a host management interface for communicating with the POT. In the event of a link failure, the computer processor determines a second set of parameters to control the one or more dispersion compensation module(s) of the POT. The second set of parameters are different from a first set of parameters used to control the one or more compensation module(s) in the case of a first optical path. The computer processor causes the POT to use the second set of parameters in place of the first set of parameters.

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 a miniaturized ultra-strong and ultra-short laser dispersion compensation device and method. The miniaturized ultra-strong and ultra-short laser dispersion compensation device comprises a stretcher, a pre-compensation compressor, an amplifier and a compressor. The pulse laser is firstly broadened by the stretcher, partial second-order and third-order dispersion is compensated by the pre-compensation compressor, partial high-order dispersion is increased, then the pulse laser is amplified by the amplifier, and finally the pulse laser is compressed to be close to the Fourier limit pulse width by the compressor. According to the invention, the pulse laser can be broadened to hundreds of picoseconds or even nanoseconds to be amplified under the existing condition and then compressed to be close to the Fourier limit pulse width, and good light beam quality is ensured.

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 relates to the technical field of photoelectronics, and discloses a chirp parameter measuring device and method based on a directly modulated laser optical module, and the device comprises an arbitrary waveform generator, an optical module, a tunable dispersion compensation module, and an oscilloscope. The optical module comprises a directly modulated laser; the output of the arbitrary waveform generator is electrically connected with the radio frequency input port of the directly modulated laser; the output optical signal end of the directly modulated laser is connected with the input optical end of the adjustable dispersion compensation module; the adjustable dispersion compensation module is used for controlling dynamic switching between a zero dispersion state and a preset non-zero dispersion state by introducing dispersion into a link, and an output optical signal port of the adjustable dispersion compensation module is optically connected with a receiving port of the optical module; and the radio frequency output end of the optical module is electrically connected with the oscilloscope. According to the invention, the problems of long chirp parameter test time and high measurement cost in the prior art are solved, and the chirp parameter measurement method has the characteristic of being capable of realizing rapid and accurate chirp parameter measurement.

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.

An optical configuration for providing chromatic dispersion compensation in a high data rate communication system is based upon using optical dispersion compensation in the receive signal path prior to performing an O / E conversion. The performance of chromatic dispersion compensation in the optical domain thus presents a “corrected” optical signal as an input to the photodetecting device. The inclusion of optical-based chromatic dispersion compensation allows for a higher data rate to be used without introducing an unacceptable bit error rate; alternatively, the use of optical-based dispersion correction allows for the reach of a data communications network to be increased.

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 invention discloses an ultrahigh repetition frequency adjustable ultrashort pulse cluster generator which comprises a mode-locked fiber laser, a first fiber coupler, a fiber delay line, a dispersion compensation fiber, a second fiber coupler, a fiber amplifier and an acousto-optic modulator. The first optical fiber coupler, the optical fiber delay line, the dispersion compensation optical fiber, the second optical fiber coupler and the optical fiber amplifier are sequentially connected end to end to form an optical fiber annular cavity, and the annular cavity is used as a frequency increasing device for pulse multiplication; the length difference between the optical fiber annular cavity and a mode-locked cavity in the mode-locked optical fiber laser is adjusted through the optical fiber delay line, and frequency increasing is carried out by using a vernier effect generated by time delay; the ultrahigh repetition frequency ultrashort pulse cluster laser output with adjustable parameters is realized through gain adjustment in the optical fiber annular cavity and synchronous pulse pickup outside the cavity. According to the technical scheme, the structural design is reasonable, the structure is simple, stability is good, sub-pulses are strictly equidistant, parameters are flexible and adjustable, and practicability is good.

The invention relates to the technical field of optical communication, and discloses a dispersion-free optical fiber coupler adaptive to double light sources, which comprises a shell, a plurality of connecting pipes for optical fiber connection are arranged at the end part of the shell, a working cavity and a connecting end connected with the working cavity are arranged in the shell, and after an optical fiber is connected with the connecting pipes, a fiber core is positioned in the connecting end; and an adjusting mechanism for adjusting the distribution proportion of the optical fiber signals is arranged in the working cavity. Through the deflection of the dispersion compensation optical fiber, the dispersion of the optical signal can be effectively compensated in the transmission process, so that the integrity and stability of the signal are kept. Meanwhile, a micro motor and a threaded rod are used for adjusting the shape of the working cavity, and primary adjustment of the optical signal output proportion is achieved; furthermore, the output angle of the optical signal is accurately controlled by adjusting the refractive index of the lithium niobate crystal, so that the distribution proportion of a plurality of optical fiber signals is optimized, and the requirements of multi-wavelength optical signals are met.

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 present invention relates to a method for maintaining the synchronization of a Fourier domain mode locked (FDML) laser, wherein the FDML laser has at least one dispersion compensation resonator having at least one variable wavelength selective optical filter, wherein the laser propagates in the resonator at a round-trip propagation frequency, and the filter repeatedly changes in terms of its wavelength selectivity at a tuning rate, and wherein the FDML laser is synchronized when the tuning rate is an integer multiple of the round-trip propagation frequency, characterized in that the method has the following steps: a. coupling out at least a part of the laser from the resonator; b. detecting at least a part of the coupled-out laser by means of at least one photodetector; c. counting the offset in the signal of the photodetector during successive counting time intervals; d. adjusting the round-trip propagation frequency or the tuning rate such that the ratio of the count value to the length of the counting time interval remains within a predetermined desired value range.