361results 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 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%.

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 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.

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.

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.

An electro-optic modulator (EOM) includes a first electro-optic (EO) material configured to receive light. The first EO material has an optic axis that is not parallel to the optical axis of the EOM. The optic axis indicates the direction through the first EO material along which a ray of light passing through the first EO material experiences no birefringence. The EOM also includes a polarization rotator that receives light output from the first EO material. The rotated light passes through a second EO material. The second EO material is positioned in the EOM such that its optic axis is not parallel to the optical axis of the EOM. The second EO material compensates for the birefringence and / or higher-order optical effects of the first material, thus reducing optical transmission errors of the EOM. The EOM may provide a wider field of view for imaging systems.

The invention relates to a phase noise compensation method and a distributed optical fiber sound wave sensing system. The method comprises the following steps: S1, simultaneously receiving a light source phase noise signal and a coherent receiving signal of a scattering signal for sensing through a group of coherent receivers; s2, performing low-pass and high-pass filtering on the coherent receiving signal, and extracting a light source phase noise reference signal and a sensing signal; s3, on the basis of the phase noise reference signal, respectively performing phase noise extraction and reconstruction on the transmitted detection optical signal and the local oscillation optical signal in the coherent receiving process; s4, compensating phase noise introduced by local oscillation light according to the reconstructed phase noise signal, and performing time domain and frequency domain reconstruction on the detection light signal to obtain a matched filtering kernel function after phase noise compensation; and S5, carrying out signal demodulation based on the coherent receiving signal after phase noise compensation and the reconstructed matched filtering kernel function. Compared with the prior art, high-precision phase noise compensation can be realized under the condition of low complexity.

The invention discloses a frequency self-matching frequency domain quantum interference method and system and an intermediate node device, and relates to the technical field of light quantum information. The method comprises the steps that a first signal set from a first user side is received through a first optical fiber, a second signal set from a second user side is received through a second optical fiber, the first signal set comprises a first quantum optical signal and a first reference optical signal, and the second signal set comprises a second quantum optical signal and a second reference optical signal; the first signal group and the second signal group meet a preset wavelength condition; performing wave splitting on the first signal group and the second signal group to obtain a quantum optical signal group and a reference optical signal group; determining a target modulation signal according to the reference optical signal group; and acting the target modulation signal on the first quantum optical signal and the second quantum optical signal to enable the first quantum optical signal and the second quantum optical signal to generate frequency domain non-degenerate quantum interference. According to the method, the intermediate node does not need to deploy a complex feedback control device.

An optical filter control apparatus according to the present disclosure includes: a compensation characteristic estimation unit configured to receive a received signal extracted from an optical signal that has passed through an optical filter provided in an optical transmission line and configured to transmit the optical signal having a predetermined frequency setting value, and estimate a compensation characteristic for compensating for waveform distortion due to a transmission path of the received signal; a frequency deviation estimation unit configured to estimate a frequency deviation between the frequency setting value and a reception frequency value acquired from the received signal; and a setting value calculation unit configured to calculate an optical filter setting value to be set in the optical filter by using the compensation characteristic adjusted based on the frequency deviation.

This invention relates to the fields of optical fiber communication and microwave photonics. Existing tunable dual-passband microwave photonic filters suffer from poor passband stability and cannot meet practical application requirements. This invention provides a narrow-band tunable dual-passband microwave photonic filter using a Brillouin fiber laser. It generates dual-tone pump light to excite the Brillouin using a tunable laser source and an intensity modulator. Combined with a Brillouin fiber oscillator and a cascaded Fabry-Perot cavity, the Brillouin gain spectrum is narrowed to the kHz level. Simultaneously, the different periodic resonant frequencies of the two ring cavities effectively suppress side modes, filtering out the desired frequency band signal. Furthermore, by synchronously tuning the center frequencies of the two passbands of the filter by changing the pump light wavelength, and simultaneously controlling the output frequency of the signal generator, the frequency interval between the two passbands is changed, ultimately realizing a narrow-linewidth tunable dual-passband microwave photonic filter.

To provide an optical transmission device, an optical transmission system, and an optical transmission method that suppress an OSNR penalty due to return light.SOLUTION: An optical transmission device disposed at a fiber end of a single-core optical fiber and used when signal light is bidirectionally transmitted through the optical fiber, the optical transmission device comprising an optical transmitter configured to transmit first signal light in one direction belonging to the signal light, an optical receiver configured to receive second signal light in a reverse direction belonging to the signal light, and a controller configured to guide the first signal light transmitted from the optical transmitter to the optical fiber, An optical circulator configured to guide the second signal light from the optical fiber to the optical receiver; and a light source configured to output, to the optical fiber, excitation light that Raman-amplifies the second signal light to second optical power higher than first optical power of the first signal light.SELECTED DRAWING: Figure 2

A multipath interference analysis device includes a statistical amount calculation unit that calculates statistical amounts of respective measurement values of splice loss measured from a plurality of optical fiber pieces for forming an optical transmission line, and measurement values of cutoff wavelength, a determination unit that determines a truncated normal distribution from a normal distribution of the cutoff wavelength, a random number generation unit that generates random numbers for selecting a predetermined number of pieces of splice connection targets of the optical transmission line, and an MPI value calculation unit that calculates an MPI value using a mode dependent loss of a fundamental mode of the optical transmission line formed of each piece selected according to the random numbers, and a splice interval.

The present invention provides an optical transmission system that can satisfy the XT required by the modulation method even if there is a difference in inter-core loss in the MCF. The optical transmission system of the present invention includes: a multicore optical fiber having a plurality of core regions, in which the loss is different between at least two cores; a front excitation light source and a combining section for causing Raman amplification excitation light in the same direction as the signal light to be incident on each core of the multicore optical fiber; a rear excitation light source and a combining section for causing Raman amplification excitation light in the opposite direction to the signal light to be incident on each core of the multicore optical fiber; characterized in that the intensity ratio of the front excitation light and the rear excitation light (the ratio of the power of the excitation light is set to a prescribed value) is controlled to reduce the variation in inter-core crosstalk (XT).

Systems and methods for operating a passive optical network (PON) extender. The methods comprise: receiving, by the PON extender, a first optical signal from a remote node device of a passive optical network via a first optical link; amplifying the first optical signal using a Raman amplifier of the PON extender to obtain a first Raman amplified optical signal; amplifying the first Raman amplified optical signal using a first optical amplifier of the PON extender to obtain an amplified uplink signal (wherein the first optical amplifier is different than the Raman amplifier); and passing the amplified uplink signal to an optical line terminal via a second optical link (wherein the optical line terminal is disposed locally at a hub site along with the PON extender).