34results about "Distortion/dispersion elimination" patented technology

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 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.

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.

Embodiments of the application disclose a paging method and related device, storage medium and computer program product. A first network element is co-located with a satellite gateway station. The paging method applied to the first network element comprises: receiving system messages broadcast by each satellite of N satellites; wherein N is a positive integer, and the N satellites are over-the-top satellites connected with the satellite gateway station; for each satellite of the N satellites, a corresponding set of satellite ephemeris parameters is parsed from the respective system message, and N sets of satellite ephemeris parameters are obtained; in response to a reporting instruction sent by a first core network, M sets of satellite ephemeris parameters currently effective in the N sets of satellite ephemeris parameters are reported to the first core network, so that the first core network determines a first satellite providing services for a non-terrestrial network (NTN) terminal from M satellites corresponding to the M sets of satellite ephemeris parameters, and pages the NTN terminal; wherein M is a positive integer, the first core network is a core network to which the NTN terminal belongs, and the NTN terminal is a call object of a ground cellular terminal.

This application provides a communication device, a base station, and a communication system. The communication device includes a power divider, a coupler group, and a multiplexer that are sequentially connected. The power divider is connected to the coupler group via at least two first paths. The power divider may divide a light beam into at least two split light beams, each split light beam is transmitted to the coupler group via one first path, and a phase difference and a time difference exist in transmission of any two split light beams in corresponding first paths. The coupler group performs coupling interference on the received at least two split light beams, and outputs at least two coupled split light beams, where each coupled split light beam passes through one second path and then enters the multiplexer, and a time difference exists in transmission of any two coupled split light beams in corresponding second paths. The multiplexer may perform orthogonal beam combining on the received coupled split light beams. The communication device may perform dispersion compensation on the light beam to suppress pulse broadening, thereby reducing a bit error rate of optical signal transmission and reducing a power loss of an optical signal.

The invention concerns an addressing device (1) arranged for being associated with an addressable optical fiber (15) and arranged to give an optically coded address to the addressable optical fiber (15) with which it is arranged to be associated, the optically coded address comprising a plurality of optical address digits, the addressing device being arranged so that each of the optical address digits is created by an address signal coming from the addressing device. The invention also relates to an optical fiber associated with an addressing device, and system and method for addressing optical fibers.

Methods and apparatuses for IQ time skew calibration in a coherent transceiver are described. A four-channel signal is received. A set of inputs is constructed for a 4x8 MIMO equalizer by converting the four-channel signal into four complex inputs that each have a phase shift corresponding to an estimated carrier frequency offset. The set of inputs further includes conjugate replicas of the four complex inputs. Using output from the 4x8 MIMO equalizer, equalizer coefficients are calculated by minimizing error between the MIMO output and a reference signal. Receiver and transmitter IQ skew are estimated using the equalizer coefficients, by converting the equalizer coefficients form the time domain to the frequency domain to determine receiver and transmitter IQ differential phase responses, which are indicative of respective receiver and transmitter IQ skew in the time domain. Skew compensation is then performed.

Transmitters, receivers, systems and methods for compensating for polarization drift caused by a communications channel are provided. One or more polarization reference signal(s) or sets of polarization reference signals may be transmitted in combination with a polarized communications signal. The combination may be via wavelength or time multiplexing. Polarization measurements of the one or more polarization reference signals or sets of polarization reference signals and subsequent heterodyne detections thereof may be used for compensation of the polarization drift of the combined signals which are received. The polarization compensation may be for a State of Polarization (SOP) of a polarized communications signal such as any one polarization basis. The polarization compensation may be for complete polarization channel compensation such as for three different polarization basis which are mutually unbiased.

To prevent the level of a RF signal obtained by photoelectrically converting modulated light from becoming excessively small.SOLUTION: A first communication device, which is located in a first site among a first and a second site that are connected by a first optical fiber, comprises: first addition means that adds up a first RF signal, of which a first frequency in a radiofrequency (RF) band is modulated, and a first sinusoidal signal of a second frequency in the RF band; and first modulation means that modulates double sidebands of an optical carrier with a signal that includes the first RF signal and first sinusoidal signal outputted by the first addition means, so as to generate a first modulated light. It is determined such that the sum of or the difference between the first and second frequencies is equal to a prescribed third frequency, and that the level of the second RF signal of the third frequency obtained by photoelectrically converting the first modulated light after being transmitted through the first optical fiber falls within a prescribed range.SELECTED DRAWING: Figure 2

Embodiments of this application disclose a signal processing method and a related apparatus. The signal processing method may be applied to an optical communication scenario. The method in embodiments of this application includes: a transmitter inverts polarities of some symbols in a first modulated signal to obtain a second modulated signal, so that an absolute value of a sum of values of all symbols in the second modulated signal is less than an absolute value of a sum of values of all symbols in the first modulated signal. In this way, power of a low-frequency part in the second modulated signal is suppressed. In addition, the receiver performs inverse transformation of power spectrum adjustment on the received signal based on identification information, to restore the original signal that is before the transmitter performs power spectrum adjustment.

An electro-optical chip includes a plurality of transmit macros, each of which includes an optical waveguide and a plurality of ring resonators positioned along the optical waveguide. An optical distribution network is implemented onboard the electro-optical chip. The optical distribution network has a plurality of optical inputs and a plurality of optical outputs. The optical distribution network conveys a portion of light received at each and every one of the plurality of optical inputs to each of the plurality of optical outputs, such that light conveyed to each of the plurality of optical outputs includes all wavelengths of light conveyed to the plurality of optical inputs. Each of the plurality of optical outputs is optically connected to the optical waveguide in a corresponding one of the plurality of transmit macros. The electro-optical chip is optically connected to a remote optical power supply.

The application discloses an optimization design method of a combining and separating wave device and a long-distance transmission 5G front transmission system, and relates to the technical field of optical communication. The method comprises the following steps: acquiring a theoretical value of total loss of the combining and separating wave device corresponding to each wavelength; designing an actual value of total loss of the combining and separating wave device corresponding to each wavelength satisfying a second condition according to the theoretical value; adjusting the optical path structure inside the combining wave device and the separating wave device in the front transmission system according to the actual value, so as to match the change of fiber loss with the wavelength and the change of the loss of a dispersion compensation device with the wavelength; and placing the dispersion compensation device on the optical path main path of the combining wave device or the separating wave device and connecting the dispersion compensation device with the common end of the combining wave device or the separating wave device, so as to perform full-wave dispersion compensation and optimize the dispersion cost. Through the flexible optimization design of the combining and separating wave device and the optimization of the dispersion cost by cooperating with the full-wave dispersion compensation, the combining and separating wave device is applied to the front transmission system, and the optimal system performance is realized.

Dispersion compensating phase filters, their method of manufacture and use are presented. The phase filters are designed to compensate for chromatic dispersion accumulated by a telecommunication optical signal when travelling in a dispersive line. The phase filter is made by first determining a target dispersion compensating phase profile of a channel of the telecommunication optical signal. This determination involves discretizing the phase profile of the dispersive line into a plurality of frequency sub-bands over a bandwidth of the channel, each frequency sub-band having a width selected on view of compensating the chromatic dispersion. For each frequency sub-band, an average phase value of the phase profile of the dispersive line is computed, and then converted to an equivalent 2Pi-bound phase value, used in building the target dispersion compensating phase profile. A spectral filtering structure embodying the target dispersion compensating profile is manufactured.

An optical device (102, 202, 402, 502) comprising the following: an optical waveguide (104, 204, 404, 504) comprising a first semiconductor material region (110, 210, 410, 510) and a second semiconductor material region (112, 212, 412, 512) defining a transition between them, the transition being a PN junction (114, 214, 414) formed at the touching boundaries of the first semiconductor material region (110, 210, 410, 510) and the second semiconductor material region (112, 212, 412, 512); an insulating layer (116, 216, 416, 516) formed on top of the optical waveguide (104, 204, 404, 504); and a III-V semiconductor layer (118, 218, 418, 518) formed on top of the insulating layer (116, 216, 416, 516) causes an optical mode (107, 207, 407, 507) of an optical signal traveling through the optical waveguide (104, 204, 404, 504) to overlap with the first semiconductor material region (110, 210, 410, 510), the second semiconductor material region (112, 212, 412, 512), the insulating layer (116, 216, 416, 516), and the III-V semiconductor layer (118, 218, 418, 518), thereby causing a phase shift in the signal traveling through the optical waveguide (104, 204, 404, 504) running optical signal is created.

An optical telecommunications network (100) comprising a / an: Ultra-Stable Signal Optical Source, USS-OS (105), for generating an Ultra-Stable Optical Signal (130), USOS; first Interferometric Stabilisation Device (110-1), ISD, connected to the USS-OS; second ISD (110-2) arranged remotely to the USS-OS and the first ISD; first Optical Link (120-1), OL, connecting an output of the first ISD to a first endpoint (115-1), wherein said first OL is bidirectional; second OL (120-2) connecting the USS-OS to the second ISD; and bridging OL (160-1) arranged proximate the first endpoint and configured to connect the first OL to the second ISD; wherein: the first ISD is configured to: receive, as an input, the USOS from the USS-OS (310); output, to the first OL, a first modified USOS (260-1) by performing a first frequency shift upon the input USOS (320); determine a first Noise Value, NV, associated with the first OL from interferometric processing of the USOS and a first return USOS (265-1), from the first endpoint, or proximate thereto, of the first modified USOS; and subsequently correct the first modified USOS by modifying the first frequency shift so as to counteract the determined first NV, thereby to output a first corrected USOS (370); and the second ISD is configured to: receive (510), as an input, a: from the bridging OL, first noisy USOS (420-1) that is the first modified USOS (260-1) as affected by the first NV due to the first OL; and a second noisy USOS (405-2) that is the USOS as affected by a second NV due to the second OL; generate a second modified USOS (260-2) by performing a second frequency shift, different to the first frequency shift, upon the second noisy USOS (520); determine the second NV from interferometric processing of the first noisy USOS and the second modified USOS; and subsequently correct (560) the second modified USOS by modifying the second frequency shift so as to counteract the determined second NV, thereby to output a second corrected USOS (420-2).

The invention relates to a bidirectional communication device between a first terminal (4) and at least one second terminal (6), comprising: - a single optical fiber (2) between the first terminal (4) and at least one second terminal (6); - the first terminal (4) comprising a radiation source (8) at at least one first wavelength (λ1), a photodetector (10), and means (12) for directing a signal from the second terminal (6) via the optical fiber (2) to the photodetector (10) and for directing a signal from the radiation source (8) to the optical fiber (2); - the second terminal (6) comprising at least one modulator (24), a photodetector (22), and power supply means (9). Figure 1

This disclosure relates to the optical communication technology, and more particularly to an optical fiber dispersion compensation adaptive amplification method and apparatus thereof, the method comprising: obtaining a dispersion compensation value of a dispersion compensation module; redistributing the total gain of the dispersion compensation module to a plurality of optical fiber amplifiers based on the dispersion compensation value; calculating a first expected attenuation value for each variable optical attenuator installed in each optical fiber amplifier based on the redistributed gain of each optical fiber amplifier, simultaneously calculating the attenuation compensation amount for each variable optical attenuator based on the dispersion compensation value; calculating a second expected attenuation value based on the first expected attenuation value and the attenuation compensation amount; calculating an actual attenuation value based on the detected power of the first input terminal and the detected power of the first output terminal of the variable optical attenuator; and comparing the actual attenuation value with the second expected attenuation value, stopping the adjustment of the variable optical attenuator if they match, and continuing the adjustment if they do not match.

This invention discloses a neural network equalization method embedding signal-related noise variance. The method includes: removing the cyclic prefix from the received time-domain signal, performing a fast Fourier transform, and removing Hermitian symmetry to obtain N frequency-domain signals; obtaining the photon count variance detected by a single SPAD in the nth sampling period based on the N frequency-domain signals, and then obtaining the photon count variance detected by the array; modeling the time-domain signal equalization as a DNN-SDN network, using the photon count variance as the input data of the DNN-SDN network; after offline training of the DNN-SDN network, deploying the network in a receiver for signal equalization. This invention can effectively suppress signal distortion caused by SPAD nonlinearity and underwater channel attenuation, thereby significantly reducing the bit error rate, increasing the communication distance of optical signals, and simplifying the complexity of the receiver.

To provide a characteristic estimation device and method, and an optical transmission system that reduce the cost or burden of the work of estimating characteristics of an optical fiber transmission line.SOLUTION: In an optical transmission system that transmits an optical signal via an optical fiber transmission line, a fiber type estimation device for estimating characteristics of the optical fiber transmission line includes a profile generation unit, a span detection unit, and a dispersion coefficient calculation unit. The profile generation unit generates a power profile representing a relation between an amount of dispersion corresponding to a transmission distance from a transmitting node or an optical transmission device and power of the optical signal, based on a received electric field information signal representing an electric field of the optical signal received by the optical transmission device via the optical fiber transmission line. The span detection unit detects one or more spans forming the optical fiber transmission line using the power profile. The dispersion coefficient calculation unit calculates a dispersion coefficient of the optical fiber transmission line by dividing the amount of dispersion estimated based on the power profile for each span by a corresponding span length.SELECTED DRAWING: Figure 6

A method and apparatus for improving transmission in an optical communication system, the method comprising: receiving an optical signal; equalizing the optical signal using an optical equalization filter to obtain an equalized optical signal; converting the equalized optical signal into an electrical signal; comparing the electrical signal with an expected electrical signal to obtain a comparison result; determining one or more optical parameters to be modified for the optical equalization filter based on the comparison result; determining modifications to be applied to the optical equalization filter based on the optical parameters to be modified; applying the modifications to the optical equalization filter; thereby determining the strain on the optical signal in the electrical domain; and applying modifications in the optical domain to correct the strain on the optical signal.

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).

The invention relates to a method of operating a bidirectional optical transmission link, wherein the optical transmission link (100) comprises a first and a second optical transceiver (102, 104) at a dedicated end of the optical transmission link (100) and an optical path (106) connecting the first and second optical transceiver (102, 104), wherein the optical transceivers (102, 104) apply the methods of converting an electrical digital transmit signal (Tel,1, Tel,2) into an electrical PAM-n transmit signal (TPel,1, TPel,2), pre-emphasizing the electrical PAM-n transmit signal (TPel,1, TPel,2) by digital filtering and using the pre-emphasized electrical PAM-n signal (TPel,1, TPel,2) as modulating signal for optically modulating an optical carrier signal, wherein the optical modulation method deployed is configured to create an optical PAM-n transmit signal (TPopt,1, TPpot,2) with a positive or negative chirp, and wherein, for initializing the optical transmission link (100), an initialization process is performed in which at least one loop comprising the following steps is run through: • creating, in the first optical transceiver (102), an optical PAM-n training transmit signal (TPopt,1) and transmitting it to the second optical transceiver (104), the optical PAM-n training transmit signal (TPopt,1) being created using an electrical PAM-n training transmit signal (TPel,1) comprising a binary training sequence, wherein initial values for filter parameters are used for pre-emphasizing the electrical PAM-n training transmit (TPel,1) signal and wherein an initial value is used for a chirp parameter that defines the positive or negative chirp of the optical PAM-n training transmit signal (TPopt,1); • receiving, in the second optical transceiver (104), the optical PAM-n training transmit signal (TPopt,1) as an optical PAM-n training receive signal (RPopt,1) using direct detection, wherein the optical PAM-n training receive signal (RPopt,1) is converted into an electrical PAM-n training receive signal (RPel,1); • obtaining sampled values of the electrical PAM-n training receive signal (RPel,1) by sampling this signal at predetermined points in time; and • using the sampled values obtained and corresponding sampled values of an ideal electrical PAM-n transmit signal to determine operating values for the filter parameters and an operating value for the chirp parameter. The operating values for the filter parameters and the operating value for the chirp parameter are then deployed during normal operation of the optical transmission link (100) in the first optical transceiver (102). Further, the invention relates to a corresponding bidirectional optical transmission link.

This application provides a time-frequency transfer system, a filtering method, and related equipment. The time-frequency transfer system includes at least a laser, a modulator, a signal source, a multi-stage repeater amplifier, a Fabry-Perot cavity filter, an optical fiber coupler, an optical power meter, a photodetector, a receiver, a radio frequency power meter, a processor, and a regulator. The optical signal output from the Fabry-Perot cavity filter is input to the optical power meter, the photodetector, and the receiver via the optical fiber coupler. The processor receives optical power data and radio frequency power data, and calculates first feedback data and second feedback data. The wavelength of the laser is adjusted using the first feedback data, and the cavity length of the Fabry-Perot cavity filter is adjusted using the second feedback data, so that the transmission peak of the Fabry-Perot cavity filter can coincide with the optical carrier and the two modulation sidebands, thereby accurately filtering out the ASE noise generated by the time-frequency transfer system.

An optical telecommunications network (100) comprising a / an: Ultra-Stable Signal Optical Source (105), USS-OS, for generating an Ultra-Stable Optical Signal (130), USOS; first Interferometric Stabilisation Device (110-1), ISD, connected to the USS-OS; second ISD (110-2) connected to the USS-OS; first Optical Link (120-1), OL, connecting an output of the first ISD to a first endpoint (115-1), wherein said first OL is bidirectional; second OL (120-2) connecting an output of the second ISD to a second endpoint (115-2); and circulating OL arranged to circulate an optical signal from, and then back to, the second ISD via the second OL and the first OL; wherein: the first ISD is configured to: receive, as an input, the USOS from the USS-OS (310); output, to the first OL, a first modified USOS (260-1) by performing a first frequency shift upon the input USOS (320); determine a first Noise Value, NV, associated with the first OL from interferometric processing of the USOS and a first return USOS (265-1), from the first endpoint, or proximate thereto, of the first modified USOS; and subsequently correct the first modified USOS by modifying the first frequency shift so as to counteract the determined first NV, thereby to output a first corrected USOS (370); the second ISD is configured to: receive (510), as an input, the: USOS from the USS-OS; and first NV; output, to the second OL, a second modified USOS (260-2) by performing a second frequency shift, different to the first frequency shift, upon said input USOS (520); receive, as a further input, a second return USOS (265-2) of the output second modified USOS from the circulating OL and thus via the first OL and the second OL (530); determine a second NV associated with the second OL from interferometric processing of the USOS and the second return USOS, and by using the received first NV; and subsequently correct the second modified USOS by modifying the second frequency shift so as to counteract the determined second NV, thereby to output a second corrected USOS (570).

The application discloses a kind of photonic spectrum analysis methods based on Mach-Zehnder interference structure.The method includes the following steps: the color dispersion stretching of fixed heavy frequency chirp-free light pulse signal is carried out;The stretched signal is electro-optically modulated with the radio frequency signal to be measured;Make modulated light signal pass through a Mach-Zehnder interference structure, and the optical path length of the Mach-Zehnder interference structure is set as the optical path length of the chirp-free light pulse repetition period in optical fiber, so that adjacent period optical pulse interference is generated;The dispersed compressed optical signal is converted into electrical signal, and the amplitude of the electrical signal is related to the phase jump between adjacent periods of the radio frequency signal to be measured, and then the detection of the relative phase jump of the radio frequency signal to be measured is realized.The application also discloses a kind of photonic spectrum analysis devices based on Mach-Zehnder interference structure.Compared with prior art, the application can realize relative phase jump perception, thereby realizing effective detection of radio frequency signal phase information.

Proposed is a technology for compensating for the performance of a transmitter using a pre-distortion method in an optical communication system, wherein a signal sending apparatus may include a transceiver, and at least one controller operably connected to the transceiver, wherein the at least one controller is configured to receive a digital signal, to modulate the digital signal into a PAM signal, to provide the PAM signal to a signal receiving apparatus, to obtain a distortion coefficient value from the signal receiving apparatus, to perform a nonlinear pre-distortion on PAM signals on the basis of the distortion coefficient value, and to provide a result signal generated on the basis of the nonlinear pre-distortion to the signal receiving apparatus.

The optical communication system of the present application has: a laser light source; an optical modulator that generates an optical signal by modulating light from the laser light source based on a first electric signal; a dispersion adding section that adds a prescribed amount of dispersion to the optical signal generated by the optical modulator; and an optical-electric conversion section that generates a second electric signal of a level corresponding to the intensity of the optical signal to which the dispersion has been added by the dispersion adding section.

The disclosed methods include recording pulse data indicating laser pulse(s) transmitted into or out of one or more fibers within a fiber cable to generate a first fiber record. The method determines whether at least one of the one or more fibers is spliced following which a trace in the first fiber record corresponding to a splicing point within the fiber cable is identified. The fiber record may be split into an inbound section and an outbound section such that an outbound trace numbering of the outbound section is mirrored to align with a trace numbering of the inbound section to generate mirrored data. Geometry data may be assigned to the mirrored data to generate a geometrically formatted fiber record. Signal components within the geometrically formatted fiber record may be reconstructed and used in a combination process to generate a report indicating captured measurements along the fiber cable.