514results about "Distortion/dispersion elimination" patented technology

The invention provides a well drilling anti-interference communication system based on a VCSEL (Vertical Cavity Surface Emitting Laser), the VCSEL and a manufacturing method thereof, and the manufacturing method comprises the following steps: calculating the light field intensity distribution of a high-order transverse mode through an intrinsic mode expansion method and a Laguerre-Gaussian model based on the epitaxial structure parameters of a laser; determining a target area which begins to perform downward annular etching on the surface of the p-DBR layer, wherein the target area coincides with a light field intensity peak area of the high-order transverse mode; performing annular etching in the target area to form an annular groove, and etching at least seven pairs of p-DBR layers inwards in the groove; the communication system comprises a signal transmitting end arranged on the derrick side, and the signal transmitting end is provided with the vertical cavity surface emitting laser; the p-DBR region of the vertical cavity surface emitting laser is provided with an annular etching structure; the graded-index fluorinated plastic optical fiber is used as a transmission medium and is connected with the derrick side and the logging room side; and the optical signal receiving end is arranged at the logging room side and is used for receiving and converting the optical signal into an electric signal.

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 relates to the technical field of automobile lamp communication, in particular to an automobile headlamp free optical communication system and method based on stroboscopic modulation. The vehicle-mounted computer receives road condition information and converts the road condition information into an original bit stream, the anti-interference encoder generates an intermediate signal with a check code, the time-frequency interleaver carries out interleaving, the driving circuit modulates the interleaved intermediate signal, and the vehicle lamp receives the modulated signal and sends out an optical signal in a stroboscopic mode; a photoelectric sensor at a receiving end captures an optical signal emitted by a vehicle lamp, a noise reduction filtering module carries out wavelet noise reduction and filtering processing, a judgment decoding module carries out frame positioning, demodulation and verification on the processed optical signal to generate a restoration bit stream, and a vehicle-mounted computer restores the restoration bit stream into road condition information. And the voice broadcast module carries out voice broadcast on the road condition information. According to the invention, stable communication requirements between vehicles and between the vehicle and the sensing equipment in a closed or semi-closed environment in which electromagnetic signals are seriously disturbed can be met.

The invention discloses a wavefront distortion correction method based on a dynamic adaptive MESSA algorithm and a coherent free space optical communication system. The problems that an existing method is prone to falling into a local optimal solution, the correction effect is poor under dynamic turbulence, and the adaptive capacity is weak are solved. According to the method, an individual position is initialized through a Circle chaotic mapping method, iterative optimization is carried out in combination with a Levy flight strategy and a variable spiral search strategy, and a step size control parameter, a safety threshold, spiral strength and a spiral adjustment coefficient are dynamically adjusted through a double-discrimination dynamic adaptive parameter adjustor. And reducing the population scale according to a nonlinear population reduction strategy, finally outputting an optimal individual position, and driving the deformable mirror to perform wavefront correction according to a control voltage vector corresponding to the optimal individual position. According to the invention, the dynamic adjustment of the algorithm parameters and the population structure is realized, and the adaptability, convergence speed and stability of the wavefront distortion correction method in the dynamic turbulence environment are enhanced.

The invention provides a transmitting-receiving axis deviation compensation method based on transmitting optical axis nutation scanning, and the method comprises the steps: carrying out the parameter pre-configuration of a space laser communication system through simulation, then initializing a variable, entering a nutation cycle, collecting the optical power data of a plurality of sampling points through a receiving end, and carrying out the nutation scanning according to the collected optical power data through a gradient acceleration nutation algorithm, calculating an optical power gradient and an optimal direction, adaptively adjusting a nutation step length, updating a pointing coordinate according to the adjusted nutation step length, judging whether convergence is carried out or a preset maximum period number is reached, and outputting a result after circulation is finished. Under the same precision, the number of iterations is reduced by about 50%-60% compared with a traditional nutation algorithm, additional data acquisition is not added, equipment such as a pyramid does not need to be additionally prepared, hardware overhead is saved, and parameter robustness is high.

The invention discloses a power data network wide area synchronous transmission system based on APN6 intelligent slicing, and relates to the technical field of power system communication, the service type of current transmission data is obtained through an identification embedding module, and a structured APN6 identifier is embedded in a Hop-by-Hop option header of an IPv6 extension header; the slice creation module judges whether retransmission is carried out or not according to CRC verification, dynamically creates multi-level slices according to time delay levels, and calculates an optical fiber refraction compensation value according to topological path coding; when the phase compensation module monitors that a line fault or a node is overloaded, different strategies are executed for slices of different levels, and transmission phases of slices around a fault area are adjusted through the signal modulation module; and when the slice capacity expansion module detects that the new energy cluster oscillates, bandwidth directional capacity expansion is executed according to the slice resource elastic scheduling framework. According to the method and the device, the data identification accuracy and the slice resource adaptability are improved.

An optical device includes a transition unit in which a first waveguide and a second waveguide are disposed in an overlapped manner such that a magnitude relationship of an effective refractive index between the vertical modes propagating the first waveguide and the vertical modes propagating the second waveguide is inverted at the positions of input and output. The transition unit allows, at the input, the second waveguide to be a single mode waveguide and allows, at the output, the second waveguide to be a multi-mode waveguide through which TM0 light in the maximum vertical mode and light in a higher-order mode propagate. The optical device includes a removing unit that allows the second waveguide to be a single mode waveguide through which the TM0 light propagates by removing the light in the higher-order mode from the light received from the transition unit.

An equalization optimizer (300) analyzes successive samples of at least one channel-related parameter (Pc) so as to determine contribution values of one or more time-reference classes representative of timescales of impact of channel impairments on response of an optical channel. The equalization optimizer (300) obtains environmental conditions data (Ed) representing environmental conditions at which equalization-related operations have to be performed. The equalization optimizer (300) performs channel inference so as to determine a contribution value for one or more remaining time-reference classes among said time-reference classes by relying on information learnt (Ld) from another channel in similar environmental conditions. The equalization optimizer (300) determines a value of at least one equalization-related parameter (Pe) according to the contribution values of the time-reference classes, and configures the equalization-related operations in accordance.

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 present invention relates to the field of communication and sensing, and specifically to a communication and sensing integrated device based on a seven-core optical fiber interferometer and an application method therefor. The application method comprises: a first beam splitter splitting, into reference light and signal light, a light source emitted by a narrow linewidth laser; performing modulation by means of a first coherent optical transmitter and a second coherent optical transmitter; amplifying the light by means of a first amplifier and a second amplifier, and then enabling the light to pass through a multi-core optical fiber from a fan-in end, and to output from a fan-out end; performing beam splitting by means of a second beam splitter and a third beam splitter, and performing demodulation by means of a first coherent receiver and a second coherent receiver; and finally, a phase-locked loop performing interference elimination on preliminarily-demodulated reference light and preliminarily-demodulated signal light to obtain finally-demodulated reference light and finally-demodulated signal light. The present invention uses a phase-locked loop to further eliminate disturbance noise of reference light and signal light. Therefore, noise interference is eliminated in continuous low-frequency detection, thereby improving the communication and sensing effect.

An equalization optimizer analyzes (S401) successive samples of at least one channel-related parameter Pc so as to determine contribution values of time-reference classes representative of timescales of impact of channel impairments on response of an optical channel. The equalization optimizer determines (S402) a value of at least one equalization-related parameter Pe according to the contribution values of the predetermined time-reference classes and configures (S403) equalization-related operations in accordance. The equalization optimizer reviews (S404) the contribution value of each time-reference class at a rate of the timescale corresponding to the time-reference class in question, and updates (S406) accordingly the at least one equalization-related parameter Pe so that a part thereof which depends on the time-reference class in question is only updated, and the equalization optimizer reconfigures (S407) the equalization-related operations in accordance.

The invention provides a laser communication stable transmission method based on dynamic compensation of a transmitting optical axis, which comprises the following steps: firstly initializing variables, then establishing a link to track communication, entering SPGD circulation in the tracking process, carrying out positive and negative disturbance on an angle of a transmitting end, collecting optical power data by a receiving end, obtaining a corresponding evaluation function, counting optical power fluctuation, and adopting an improved SPGD iterative formula to determine the dynamic compensation of the transmitting optical axis. And calculating a transmitting end optical axis pointing angle of next iteration, controlling transmitting optical axis compensation according to the pointing angle, then judging whether convergence or reaching a preset maximum period number is carried out or not, if not, continuing iteration, and if so, ending circulation. In the autonomous calibration process, normal work of a communication link is kept, rapid information feedback and processing are achieved through the continuously existing communication link, the response speed and stability of the system are improved, convergence is conducted by combining an SPGD algorithm and adopting small signal jitter, accidental link breakage can be avoided to the maximum extent, and cooperative dynamic compensation of the optical axes of receiving and transmitting is achieved; and the convergence speed is improved by 50%.

According to an aspect of the present invention, there is provided an optical receiver in an optical transmission system that transmits an optical signal between an optical transmitter and an optical receiver connected via an optical fiber transmission path, the optical receiver including: a channel distribution estimation unit that estimates channel distribution information in a transmission direction based on the optical signal transmitted from the optical transmitter and a reference signal; and a non-linear compensation unit that performs non-linear compensation based on the channel distribution information estimated by the channel distribution estimation unit.

The invention discloses a system for simultaneously suppressing second-order nonlinearity and third-order nonlinearity in a direct modulation laser (DML), which belongs to the field of optical communication, and can simultaneously suppress the second-order nonlinearity and the third-order nonlinearity in the system under the condition of DSP-FREE through the combined action of a broadband pre-distortion circuit and an optical path push-pull structure. Wherein at a transmitting end, a set of Schottky diodes and Chebyshev gradient transmission lines which are connected in parallel reversely are adopted to build a DC-10GHz broadband pre-distortion module, and a radio frequency signal generates a reverse third-order intermodulation (IMD3) component through an analog pre-distortion circuit so as to counteract forward third-order nonlinearity of a laser; at a receiving end, a second-order intermodulation (IMD2) component is differentially eliminated through an optical path push-pull modulation architecture. Compared with a traditional DSP scheme, digital signal processing is not needed, the method has the advantages of being low in complexity and wide in bandwidth, and nonlinear accurate compensation of an optical communication system can be achieved.

The invention provides an instantaneous microwave frequency measuring method and device, and belongs to the technical field of wireless communication, and the method comprises the steps that a laser sends input light to a phase modulator; the phase modulator modulates a microwave signal on the input light, and after a modulated light signal is obtained, the modulated light signal is divided into multiple paths to be input into the adjustable Bragg grating array at the same time; the adjustable Bragg grating array applies different phase shifts to the multiple paths of modulated optical signals to obtain optical signals with different dispersion amounts, and then inputs the multiple paths of optical signals to a photoelectric detector; the photoelectric detector converts the multiple paths of optical signals into electric signals respectively to obtain multiple paths of microwave signal power, and inputs the multiple paths of microwave signal power into a digital signal processor; and the digital signal processor determines the instantaneous frequency of the microwave signals based on the power of the multiple paths of microwave signals. According to the invention, higher measurement precision is provided in a wide frequency range.

The invention relates to the technical field of free space optical communication, in particular to an atmospheric turbulence adaptive optical compensation method for wireless laser communication, which comprises the following steps of: performing light beam coarse tracking by using a fast reflector to eliminate tilt drift; monitoring the received light intensity of the wavefront sensor in real time, and setting a threshold value for mode judgment; when a channel is good, a Kalman filtering algorithm is adopted to predict and compensate system delay, modal decoupling is carried out on reconstructed wavefront, a large-stroke deformable mirror is controlled to correct low-frequency large-amplitude aberration, and a micro-electro-mechanical deformable mirror is controlled to correct high-frequency residual error; and when the channel is in deep fading or the detector fails, the blind optimization mode is automatically switched, the state of the large-stroke deformable mirror is locked, and SPGD iterative control is applied to the micro-electro-mechanical deformable mirror based on the communication light intensity. According to the invention, through a double-deformable mirror frequency division cooperation and hybrid sensing strategy, the problems of insufficient bandwidth, limited stroke, easy interruption and the like of a traditional system under strong turbulence are effectively solved, and the optical fiber coupling efficiency and the robustness of a communication link are significantly improved.

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 discloses a high-precision photon digital-to-analog conversion system based on noise shaping, which is characterized in that a mode-locked laser generates an optical pulse sequence, optical pulses enter a dispersive medium, and periodic pulses are processed by using a fractional order Talbot effect, so that the pulse repetition frequency is improved; the Delta-Sigma (Delta Sigma) modulation module processes a preset target signal and shifts noise to a high frequency band based on an oversampling technology and noise shaping to realize conversion from an analog signal to a digital signal; the pulse signal with the repetition frequency increased is input into the electro-optical modulation module to serve as a sampling source, and a digital signal generated by the delta-sigma modulation module is input into the electro-optical modulation module for intensity modulation, so that the optical pulse carries the characteristics of frequency change and noise shaping of the signal, and fusion from electric signal modulation to optical signal modulation is completed; inputting the pulse signal after electro-optical modulation into a photoelectric detector, and converting an optical signal into an electric pulse signal; the electric pulse signal enters a filtering module, noise in the electric signal is filtered out, and an analog signal is obtained.

The present disclosure provides signal management with unequal eye spacing by: determining a dispersion slope of a channel between a transmitter and a receiver based on a temperature of the transmitter and a wavelength used by the transmitter to transmit signals over the channel; determining maximum and minimum powers for transmission over the channel; assigning a plurality of rails to a corresponding plurality of power levels, wherein amplitude differences between adjacent rails of the plurality of rails are based on the dispersion slope and produce a first eye pattern with a first Ratio of Level Mismatch (RLM) less than one; encoding, by the transmitter, data onto a conditioned signal according to the plurality of rails; and transmitting the conditioned signal over the channel, so that the conditioned signal demonstrates a second eye pattern with a second RLM greater than the first RLM when received at the receiver.

This optical communication system comprises: a laser light source; an optical modulator that generates an optical signal by modulating light from the laser light source on the basis of a first electric signal; a wavelength dispersion addition unit that adds a prescribed amount of wavelength dispersion to the optical signal generated by the optical modulator; and a photoelectric conversion unit that generates a second electric signal at a level corresponding to the intensity of the optical signal having added thereto, by the wavelength dispersion addition unit, the wavelength dispersion.

The application relates to the field of optical communication technology, and provides a four-level modulation receiving device and method based on double-polarization double-binary superposition, which comprises a transmitting module, a transmission link and a receiving module; the transmitting module is used for outputting a first binary baseband signal, outputting a first three-level double-binary electrical signal, outputting a second binary baseband signal, outputting a second three-level double-binary electrical signal, performing polarization orthogonal superposition on the first three-level double-binary electrical signal and the second three-level double-binary electrical signal, and outputting one superimposed optical signal; the transmission link is used for transmitting the one superimposed optical signal; and the receiving module is used for receiving the one superimposed optical signal and restoring the one superimposed optical signal into the first binary baseband signal and the second binary baseband signal. The application realizes effective unification of high dispersion tolerance and high spectral efficiency by superimposing two double-binary signals on orthogonal polarization states.

The invention discloses a four-channel F-DFBS array parallel photon reserve pool optical fiber compensation method comprising the following steps: inputting a pre-processed damaged optical fiber signal into a trained optical fiber compensation model to obtain a compensation signal; wherein the optical fiber compensation model comprises a convolution preprocessing network and a four-channel F-DFBS array parallel photon time delay reserve pool network; the convolution preprocessing network is used for performing preliminary compensation on the normalized damaged optical fiber signal to obtain a preliminarily compensated damaged optical fiber signal; the four-channel F-DFBS array parallel photon time delay reserve pool network is used for carrying out secondary compensation to obtain a compensation signal; and obtaining an evaluation result of the compensation signal according to the mean square error and the error rate. According to the invention, optical fiber damage equalization can be carried out on four paths of signals in parallel, the signal recovery efficiency is obviously improved, a complex photon integrated structure is avoided, the hardware complexity and cost are greatly reduced, and a channel equalization solution which is efficient, practical and easy to deploy is provided.

The application provides an optical communication device and system, each wavelength range corresponds to a dummy light filling unit, when receiving signal light not working in full wave state (i.e. only part of the wavelength is on wave), since the input port of each dummy light filling unit only corresponds to receiving signal light of a specific wavelength range, only the dummy light filling unit of the on wave wavelength position can receive signal light, and then the remaining dummy light filling units not receiving signal light can send dummy light, thereby realizing automatic filling of dummy light. This dummy light filling method does not need to detect the on wave / off wave wavelength, and can quickly fill the energy of the wavelength position not on wave after part of the wavelength is on wave / off wave, thereby maintaining the stable operation of the wide spectrum transmission system.

A method for equalization in an access network of passive optical network type. The method includes, for a given optical distribution network connecting a given input port of an optical line termination to a given plurality of optical network units: for at least one of the optical network units of the given plurality, obtaining a distance between the optical line termination and the optical network unit; determining a representative distance associated with the given optical distribution network, according to the one or more distances obtained; determining at least one equalization parameter, according to the representative distance; and equalizing transmission channels within the given optical distribution network, according to the at least one equalization parameter, each of the transmission channels connecting the given port of the optical line termination to one of the optical network units of the given plurality.

The invention provides a method and a device for eliminating nonlinear damage in a KK receiver, which can perform accurate modeling and reconstruction on a beat frequency process between a pilot frequency and a transmission field signal as well as between the pilot frequency and a carrier field signal in a digital domain of the KK receiver, and combine least square normalization and an iterative feedback mechanism to eliminate nonlinear damage in the KK receiver. Non-linear damage introduced by pilot frequency beat frequency is effectively eliminated from a sampling receiving power signal, and residual non-linear distortion in a recovery field signal is remarkably reduced. Therefore, the requirements of the system on the bias stability of the transmitting end and the linearity of the device are reduced, the bit error rate performance is improved, the tolerance of the optical fiber transmission system on optical signal-to-noise ratio degradation and the achievable transmission distance are improved, and high-performance KK direct detection receiving in a complex nonlinear environment is realized.

An optical transceiver (101) of an optical relay apparatus includes: a coherent reception front-end unit (110) that coherently detects an input optical signal to be input, based on local oscillation light, and outputs the coherently detected first analog electric signal; a coherent transmission front-end unit (120) that coherently modulates a second analog electric signal acquired by turning around the first analog electric signal, based on transmission light, and outputs the coherently modulated output optical signal; and an analog compensation unit (130) that performs analog signal processing on the first analog electric signal in such a way as to compensate for signal quality according to a signal characteristic between an input of the coherent reception front-end unit (110) and an output of the coherent transmission front-end unit (120), and thereby generates the second analog electric signal.

The symbol constellation generating device (2000) acquires specification information (10) of an optical communication system (100). The symbol constellation generating device (2000) generates noise feature information (20) using a first estimation model (50) based on the specification information (10). The symbol constellation generating device (2000) generates a symbol constellation (30) suitable for an optical communication system having noise features represented by the noise feature information (20) using a second estimation model (60).

This optical receiving apparatus comprises a first branching unit which branches an input optical signal into a first optical signal and a second optical signal; a reception amplification unit which amplifies power of the first optical signal; a compensation unit which compensates for a wavelength distortion of the first optical signal for which the power has been amplified; a first detection unit which detects power of the second optical signal; a first control unit which controls the amount of compensation for the wavelength distortion on the basis of the power of the second optical signal; a second branching unit which branches the first optical signal for which the wavelength distortion has been compensated into a third optical signal and a fourth optical signal; a second detection unit which detects power of the third optical signal; and a second control unit which controls, on the basis of the power of the third optical signal, an amplification factor of the power of the first optical signal before the wavelength distortion is compensated.

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.

An event timing-based method and apparatus for fiber-optic frequency transfer are provided, relating to the fields of time-frequency transfer and precision time measurement. According to the method, an event timer is used to detect a time stamp of each rising edge of a radio frequency (RF) signal, which reflects a link delay jitter, a reference time stamp is subtracted from the time stamp to obtain a phase error, and an actuator is driven to compensate the phase error, thereby improving tolerance of a system to link noise while ensuring the stability of optical frequency transfer. Thus, the link delay jitter is suppressed, ensuring that a phase of an output transferred beam remains in long-term stability with a phase of an input reference light.