41 results about "Nonlinear dispersion" patented technology

The invention discloses a combined navigation method of joint entropy extended Kalman filter based on strong tracking. The combined navigation method comprises the following steps of: establishing a state equation of an aircraft navigation system; establishing a kinetic equation of an SINS / GNSS combined navigation system; establishing a measurement equation of the SINS / GNSS combined navigation system; dispersing the kinetic equation and measurement equation of the SINS / GNSS combined navigation system; linearizing a nonlinear dispersion kinetic equation; by adopting a joint entropy extended Kalman filter algorithm based on strong tracking, outputting information of SINS / GNSS combined navigation according to the linearized kinetic equation. As fading factors in the strong tracking theory are introduced into the joint entropy extended Kalman filter algorithm, model uncertainty of a non-linear SINS / GNSS combined navigation system and non-gaussian problem of noise statistical characteristics are effectively solved, the navigation precision can be improved, and the stability of the navigation process can be improved.

The invention discloses a microwave photon up-conversion device and method based on a photoelectric oscillator and belongs to the technical field of microwave photonics. The device is composed of a laser source, a first coupler, a first circulator, a first high nonlinearity dispersion displacement optical fiber, an erbium-doped optical fiber amplifier, a first photoelectric detector, a second coupler, a first Mach-Zehnder modulator, a first microwave signal source, a first direct current voltage-stabilized power supply, an optical filter, a second Mach-Zehnder modulator, a second direct current voltage-stabilized power supply, a second circular, a second high nonlinearity dispersion displacement optical fiber, a second photoelectric detector, a microwave amplifier, a double-parallel Mach-Zehnder modulator, a third direct current voltage-stabilized power supply, a fourth direct current voltage-stabilized power supply, a fifth direct current voltage-stabilized power supply, an optical isolator and a spectrum analyzer. A Brillouin frequency shift value f of the high nonlinearity optical fiber is 9.2GHz, and a signal with frequency of f<m> can be up converted to f<m>+18.4GHz, so alow quality and low frequency intermediate signal is converted into a high quality and high frequency signal.

The invention discloses an image compression and reconstruction method based on LCTF (liquid crystal tunable filter) hyperspectral imaging system; the method prevents the precision of a reconstructed image from being affected by nonlinear dispersion of the original CASSI (coded aperture snapshot spectral imaging) system, the problem that coded aperture is unmatched with pixel size of a detector is solved by means of calculating synthetic aperture size, and spatial resolution of the constructed image is improved. The minimum pixel size of the hyperspectral imaging system is the pixel size of the detector; a target spectral image sequence is acquired through the LCTF hyperspectral imaging system; shift is manually added to each single image in the target spectral image sequence, and the shifted image sequences are superposed in order to obtain a mixed image. The use of the method according to the invention is equivalent to linear dispersion, the correspondence between coded aperture pixel and detector pixel can be analyzed, and the precision of a reconstructed mage can be improved.

A phased array radio frequency pulse generator includes a plurality of radio frequency pulse generator units (4, 4a, 4b, 4c) each having a non-linear dispersive electrical circuit (1) incorporating at least one non-linear element (5) including a material sensitive to low power signals (7) and a means (6) for producing a variable power control signal (7) and applying it to be at least one non-linear element (5) to modify the extent of the non-linearity of the element and thereby vary the timing of the radio frequency electrical output signal generated, and means (13) for adjusting the value of the control signals (7) provided in each unit (4, 4a, 4b, 4c), to vary the relative phases of the output signals from the units (4, 4a, 4b, 4c) in a phased array on a pulse to pulse basis.

The invention provides a high-nonlinearity dispersion flattened photonic crystal fiber with a pentagonal core. The high-nonlinearity dispersion flattened photonic crystal fiber comprises a quartz glass substrate. Micron-size air holes which are arranged according to certain rules are formed in the substrate, are axially distributed along the fiber and are perforated through the integral fiber; the arrangement rules of the air holes include that the air holes are divided into four layers, the air holes in each layer are arranged to form a regular pentagon, the innermost layer comprises five small air holes, the five small air holes are formed in five vertexes of the corresponding pentagon, and five tiny air holes are additionally formed in positions among the small air holes; the second layer comprises ten large air holes, and five large air holes are formed in five vertexes of the corresponding pentagon; the third layer, namely the second outer layer, comprises fifteen medium air holes, and five medium air holes are respectively formed in five vertexes of the corresponding pentagon; the outermost layer comprises twenty large air holes, and five large air holes are respectively formed in five vertexes of the corresponding pentagon. The high-nonlinearity dispersion flattened photonic crystal fiber has the advantage that requirements of the fields of fiber communication, nonlinear optics, optical signal processing and the like can be effectively met.

The invention discloses a rapid K-space linear frequency sweep laser source. The laser source comprises a semiconductor optical amplifier, two polarization controllers, a dispersion control delay line, a circulator, a tuned filter and an output optical fiber coupler, wherein radiation light emitted from the semiconductor optical amplifier is transmitted to the dispersion control delay line through a polarization controller I; the middle port of the circulator is connected to the tuned filer through a first port of the circulator; returned signals are connected to the optical fiber coupler after passing through a third port of the circulator; one path of the optical fiber coupler outputs frequency sweep laser through a 60% port, and the other path of the optical fiber coupler is connected to the polarization controller II and then returns to a ring laser oscillation cavity; the tuned filter mainly comprises two dispersion elements, namely a grating and a prism, and a rotary polygonal mirror; and the linearity of a wave number space is achieved through combination of linear dispersion of the grating and non-linear dispersion of the prism as well as selection on the angles and directions of the prism. The rapid K-space linear frequency sweep laser source can be used for outputting the rapid K-space linear frequency sweep laser, and can obtain the signals of the linearity of the wave number space directly without calibration when being applied to an OCT (Optical Coherence Tomography) imaging system.

The invention discloses a method of simulating the specific nonlinear wave sequence. The method includes preprocessing of the ocean measured wave sequence, accurate solution of the nonlinear dispersion relation and automatic generation of wave machine driving signals. According to the method, the observed ocean wave sequence can be automatically processed, the wave sequence obtained through oceanobservation is converted into the frequency, the corresponding amplitude and the phase information required for laboratory simulation waves according to the Froude number similarity criterion throughutilizing Fourier transform; the third-order nonlinear irregular wave interaction theory is utilized to rapidly calculate the dispersion relation of complex multi-frequency waves through the iterativecalculation method, generally, wave number accuracy of wave components can be calculated to one thousandth within ten iteration steps, and problems of low precision and long time for directly solvingthe nonlinear dispersion relation are solved.

An ultrafast all-optical true random number generation device is characterized in that an active mode-locked pulse laser, a pulse optical amplifier, a high nonlinear dispersion shifted fiber and an anomalous dispersion fiber are sequentially arranged in a polarization-preserving fiber to form a super-continuous spectrum entropy source, a pulse sequence outputted by the super-continuous spectrum entropy source is cut by an array waveguide grate to generate N narrow-band sub optical pulse sequences, enters an optical attenuator array and is adjusted, the pulse sequence and a continuous optical signal outputted by a continuous optical laser simultaneously enter an all-optical comparator array through fibers, and the pulse sequence is quantized into a high-speed true random pulse sequence, is filtered by an optical filter array, enters a fiber delay line and finally enters an optical coupler for time division multiplexing to form an ultrafast all-optical true random number sequence. High-speed true random numbers are generated by the aid of time division multiplexing technology for the first time, the requirement for the bandwidth of the entropy source is reduced, the rate reaches Tbps magnitude and is increased by three orders of magnitude as compared with an existing true random number generation rate, and security requirements of modern high-speed secure communication are met.

The invention relates to a broadband wavelength converter based on high-nonlinearity flattened-dispersion optical fibers, which comprises a signal light input optical path, a continuous light source, a continuous light input optical path and a Sagnac interference ring. The Sagnac interference ring comprises high-nonlinearity flattened-dispersion optical fibers, a first coupler and a second coupler, wherein the first coupler is used for transmitting continuous light to the Sagnac interference ring, and the second coupler is used for coupling signal light to be converted with the continuous light outputted by the first coupler and transmitting to the Sagnac interference ring. The invention further relates to a converting method of the broadband wavelength converter, which includes: using the second coupler to receive the signal lights to be converted; using the first coupler to receive the continuous light in a target conversion wavelength; and using the first coupler to output wavelength-converted signal light and the original-wavelength signal light. The broadband wavelength converter and the converting method have the advantages that wavelength conversion with wavelength interval more than 50nm can be realized; the converter is quick in response speed and can reach femtosecond level theoretically; the length of the Sagnac interference ring is only 10m; and the broadband wavelength converter is compact in structure, cost-saving and low in power consumption.

A non-linear dispersive pulse generator for producing pulsed radio frequency electrical signals includes a non-linear dispersive electrical circuit (1) incorporating at least one non-linear element (2) made of a material sensitive to low power signals and a means (5) of producing a variable power control signal (6) and applying it to the element (2) to modify the extent of the non linearity of the element (2) and thereby vary the output frequency of the radio frequency electrical signal generated by the generator.

The invention discloses a power dividing phase shifter. The power dividing phase shifter has a mixed ring structure formed by a power dividing ring and two coupling rings; the input end of the power dividing ring is used as the input of the power dividing phase shifter, the output of the power dividing ring is connected with the two parallel coupling rings, and the output ends of the coupling rings are used as the outputs of the power dividing phase shifter; the power dividing ring is provided with a plurality of corresponding loading stubs (14) for controlling a plurality of output states; each loading stub (14) is provided with a switch (15); and the corresponding loading stubs (14) are controlled by the switches (15) to output power dividing and equal difference phase signals of each state. Based on the nonlinear chromatic dispersion characteristic after the sections are loaded in a transmission line, the output of the power dividing and equal difference phase signals is realized on a micro-strip structure with power dividing function by controlling the loading stubs through the switches. The magnitude of the equal difference phase depends on the electrical length of the loading stubs. The power dividing phase shifter has compact structure, and has power dividing and phase shifting functions at the same time.

The invention discloses a tunable fiber optical parameter oscillator based on Rayleigh backscattering, and belongs to the technical field of fiber lasers. The tunable fiber optical parameter oscillator consists of a tunable laser, a first polarization controller, a phase modulator, a pulse pattern generator, a second polarization controller, an erbium-doped fiber amplifier, an optical isolator, a first circulator, a fiber bragg grating, a high nonlinear dispersion displacement fiber, a tunable band-pass filter, a wavelength division multiplexer, an erbium-doped fiber pumping laser source, an erbium-doped fiber, a second circulator, a single mode fiber and a third polarization controller. An annular structure is formed by the first circulator, the high nonlinear dispersion displacement fiber, the tunable band-pass filter, the wavelength division multiplexer, the erbium-doped fiber, the second circulator, the third polarization controller and the fiber bragg grating, and an oscillation cavity is formed together with the single mode fiber, so that random laser output is realized. The tunable characteristic of output random laser can be realized by changing the operating wavelength of the tunable band-pass filter. The tunable fiber optical parameter oscillator has the advantages of compact structure, tunable output wavelength, large tuning range and the like.

A method for extending and enhancing bright coherent high-order harmonic generation into the VUV-EUV-X-ray regions of the spectrum involves a way of accomplishing phase matching or effective phase matching of extreme upconversion of laser light at high conversion efficiency, approaching 10−3 in some spectral regions, and at significantly higher photon energies in a waveguide geometry, in a self-guiding geometry, a gas cell, or a loosely focusing geometry, containing nonlinear medium. The extension and enhancement of the coherent VUV, EUV, X-ray emission to high photon energies relies on using VUV-UV-VIS lasers of shorter wavelength. This leads to enhancement of macroscopic phase matching parameters due to stronger contribution of linear and nonlinear dispersion of both atoms and ions, combined with a strong microscopic single-atom yield.

The invention discloses a linear chromatic dispersion combined prism beam splitting device which is formed by combining two prisms made of a special selected material and provided with coating films on the side faces in the mode of 'bottom surface adhesion and opposite coating film faces'. The linear chromatic dispersion combined prism beam splitting device is especially suitable for spectral analysis, spectrum detection and other relevant fields. Based on a control variable method and a differential equation thought, the non-linear chromatic dispersion of the second prism is utilized to compensate non-linear chromatic dispersion of the first prism so as to obtain the linear chromatic dispersion combined prism beam splitting device by controlling light propagation direction and the shapes of the prisms according to the chromatic dispersion characteristic of a first prism material. The linear chromatic dispersion combined prism beam splitting device overcomes the defect of chromatic dispersion non-linearity of the single prism and has the advantages of being wide in free spectral range, high in light energy utilization rate, good in universality, simple in structure, low in price and the like.

A method for extending and enhancing bright coherent high-order harmonic generation into the VUV-EUV-X-ray regions of the spectrum involves a way of accomplishing phase matching or effective phase matching of extreme upconversion of laser light at high conversion efficiency, approaching 10−3 in some spectral regions, and at significantly higher photon energies in a waveguide geometry, in a self-guiding geometry, a gas cell, or a loosely focusing geometry, containing nonlinear medium. The extension and enhancement of the coherent VUV, EUV, X-ray emission to high photon energies relies on using VUV-UV-VIS lasers of shorter wavelength. This leads to enhancement of macroscopic phase matching parameters due to stronger contribution of linear and nonlinear dispersion of both atoms and ions, combined with a strong microscopic single-atom yield.

The invention discloses a simulation method for an electromagnetic problem containing a nonlinear dispersive medium, which comprises the following steps of: establishing a geometric model of a medium according to the geometric size of the medium of a device, subdividing the model by adopting a hexahedron unit, acquiring the geometric information of the device and setting the position information of an excitation source; performing region division on the subdivided geometric model according to the kernel number of the parallel parameters; and establishing a differential equation set by adopting a time domain discontinuous Galerkin finite element method, and solving any dispersion model and a nonlinear dispersive medium model in the geometric model of the medium. According to the method, on the basis of the time domain discontinuous Galerkin finite element, by combining the local time stepping and parallel technology, modeling of a complex medium and electromagnetic characteristic analysis of a nonlinear dispersive medium can be achieved; due to the fact that the time domain discontinuous Galerkin finite element method has the advantages of being high in precision and flexible in modeling, an inverse matrix can be directly obtained, and due to the fact that local time stepping and parallel technologies are added, the calculation time can be greatly shortened.

The invention discloses a nonlinear dispersion element-based photoelectric oscillator stress sensing system, which comprises an optical frequency comb, a polarization controller, an electrooptical modulator, a circulator, a nonlinear dispersion element, an erbium-doped optical fiber amplifier, a photoelectric detector, a DC blocking device, a low-noise microwave amplifier, a microwave power splitter and a digital processing unit. The nonlinear dispersion element is adopted as a sensing unit and a dispersion value is tuned by stress, so that the generated microwave signal frequency is encoded,and the sensing sensitivity and resolution and the demodulation speed can be effectively improved.

A method for nonlinearity compensation for an optical transmission link includes determining a dispersion effect of a transmission link; applying a phase conjugation to the transmission link, the phase conjugation responsive to an input wave over the transmission link and providing a conjugated version of the input wave; and configuring an optimum equivalent link responsive to the phase conjugation after the transmission link to compensate for a non-linear dispersion effect from said transmission link

An optical fiber is tapered, for example, by heating it with a CO2 laser. The tapering process is controlled such that the taper transition regions have taper angles selected to minimize loss. The taper waist has a diameter selected to introduce desired dispersion properties and desired nonlinearity. The optical fiber can be used as a dispersion compensator in a fiber laser or other fiber optic system. The nonlinearity in the tapered optical fiber allows the generation of ultrashort light pulses.

The invention discloses a linear dispersion combined prism optical splitter. The linear dispersion combined prism optical splitter is formed by combining two prisms which are manufactured from special materials and coated with films on the side surfaces by a mode of enabling the bottom surfaces to be clung to each other and the film-coated surfaces to be opposite to each other. The linear dispersion combined prism optical splitter is particularly suitable for the fields of spectrum analysis, spectrum detection and related fields. The linear dispersion combined prism optical splitter is on the basis of the control variable method and differential equation concept; the spreading direction of the line and the shape of the prisms are controlled according to the dispersion property of the first prism material; the nonlinear dispersion of the first prism is compensated according to the nonlinear dispersion of the second prism so as to obtain the linear dispersion combined prism optical splitter. The linear dispersion combined prism optical splitter can overcome the defect of nonlinear dispersion of single prism and has the advantages of being wide in free spectrum range, high in light energy utilization rate, high in generality, simple in structure, and small in cost.

Disclosed is a nonlinear dispersion-shifted optical fiber, wherein a charomatic dispersion at a wavelength of 1550 nm is equal to a set value required for optical signal processing utilizing a nonlinear phenomenon, a dispersion slope at a wavelength of 1550 nm falls within a range of 0.001 to 0.1 ps / nm2 / km, a margin of fluctuation of the charomatic dispersion in a longitudinal direction of the optical fiber at a wavelength of 1550 nm falls within a range of 0.01 to 3 ps / nm / km, and a nonlinear constant n2 / Aeff at a wavelength of 1550 nm is not smaller than 15x10-10 / W.

The invention discloses a snapshot type spectrum confocal sensor and a measuring method thereof, and relates to the technical field of sensors, the snapshot type spectrum confocal sensor comprises a collimating lens group, a first spectroscope, a correction plate, a micro lens array, a first focus lens, a volume grating and an area array detector, the collimating lens group is horizontally arranged, the first spectroscope is located under the collimating lens group, the first spectroscope is obliquely arranged by 45 degrees, the correction plate is horizontally arranged and located under the first spectroscope, the first focus lens is vertically arranged and located on the plane where the first spectroscope is located, the first focus lens is arranged on one side of the first spectroscope, and the first focus lens and the correction plate are in reflection mirror symmetry. The micro lens array is horizontally arranged and is positioned right below the correction plate; and according to the invention, an area array dispersion array and a system integrated nonlinear dispersion compensation method are adopted, morphology information acquisition of a snapshot type area is realized, and the method has a height or displacement resolution of micron or even dozens of nanometers.

The invention discloses a design method for a combined two-piece linear dispersion prism light splitter. The prism light splitter is designed by combining two prisms which have special materials and special shape parameters and is especially applicable to spectrum analysis, spectrum detection and related fields. According to the method, based on a control variable method and the linear programming theory, non-linear dispersion of the second prism is utilized to compensate non-linear dispersion of the first prism through controlling light spreading directions and the shapes of the prisms according to dispersion characteristics of the materials of the first prism, and the combined linear dispersion prism light splitter is acquired. The combined prism is advantaged in that a non-linear dispersion disadvantage of a single prism is solved, and properties of wide free spectrum scope, high luminous energy utilization rate, good versatility, simple structure and low cost are all realized.

The invention discloses a generation system for generating a sixfold frequency vector millimeter wave. The output end of a laser is connected with the light input end of a light intensity modulator through an optical fiber. The output end of a data source is connected with the input point of an electric amplifier through a cable. The output end of the electric amplifier is connected with the electric input end of the light intensity modulator through a cable. The output end of the light intensity modulator is connected with the light input end of a light filter through an optical fiber. The output end of a first optical filter is connected with the input end of a first optical amplifier through an optical cable. The output end of the first optical amplifier is connected with the input endof a second optical filter through a high nonlinear dispersion displacement optical fiber, the output end of the second optical filter is connected with the input end of the second optical amplifier through an optical cable, and the output end of the second optical amplifier is connected with the input end of an optical attenuator through a single-mode optical fiber. Compared with the prior art, the system has the advantages of low broadband requirement and high millimeter wave frequency.

A method for extending and enhancing bright coherent high-order harmonic generation into the VUV-EUV-X-ray regions of the spectrum involves a way of accomplishing phase matching or effective phase matching of extreme upconversion of laser light at high conversion efficiency, approaching 10−3 in some spectral regions, and at significantly higher photon energies in a waveguide geometry, in a self-guiding geometry, a gas cell, or a loosely focusing geometry, containing nonlinear medium. The extension and enhancement of the coherent VUV, EUV, X-ray emission to high photon energies relies on using VUV-UV-VIS lasers of shorter wavelength. This leads to enhancement of macroscopic phase matching parameters due to stronger contribution of linear and nonlinear dispersion of both atoms and ions, combined with a strong microscopic single-atom yield.

A method for nonlinearity compensation for an optical transmission link includes determining a dispersion effect of a transmission link; applying a phase conjugation to the transmission link, the phase conjugation responsive to an input wave over the transmission link and providing a conjugated version of the input wave; and configuring an optimum equivalent link responsive to the phase conjugation after the transmission link to compensate for a non-linear dispersion effect from said transmission link.