Abstract: The invention relates to a IM bias voltage determining method adapted to determine an IM bias voltage corresponding to a desired Quantum Bit Error Rate based on the following formula Q ? ( V IM ) = Q 0 + R err R err + R cor where Q(VIM) is the QBER dependent of the IM bias voltage VIM, Q0 is the optimal minimal QBER, Rerr is the number of erroneous detections, Rcor is the number of correct detections and VIM is the IM bias voltage.

Abstract: A method for controlling a wavelength of an optical module, includes: a laser light source unit emitting a laser beam; a wavelength filter having a periodical transmission characteristic with respect to a wavelength of light; a temperature controller on which the wavelength filter is placed and that adjusting a temperature of the wavelength filter; a heat generating body placed on the temperature controller; and a control device controlling the wavelength of the laser beam emitted from the laser light source unit and control the transmission characteristic of the wavelength filter based on an intensity of the laser beam transmitted through the wavelength filter, the method including changing at least one of a target value of the wavelength control of the laser beam and a target value of the control of the wavelength filter based on a current value of the heat generating body.

Abstract: A distorter coefficient updating apparatus, a distorter coefficient updating method, and a digital predistortion apparatus. The distorter coefficient updating apparatus is configured at an optical receiver side, and comprises a processor configured to: perform re-distortion processing on a signal after decision according to a first distorter coefficient to generate a first reference signal; and calculate a second distorter coefficient according to the first reference signal and a signal before decision, or according to the first reference signal, the signal after decision, and the signal before decision The second distorter coefficient is fed back to the processor as the first distorter coefficient of the processor in a next update, and the second distorter coefficient is fed back to a predistorter on an optical transmitter side as a predistortion coefficient for the predistorter to perform a predistortion processing on a signal input to the predistorter.

Abstract: A method (200) of controlling compensation of chromatic dispersion in an optical transport network. The method comprises determining (202) whether a residual dispersion, RD, of a first path (3) within the network is within a defined RD range and if the RD of the first path is outside the defined RD range the method comprises identifying (204) a first tuneable dispersion compensation module, TDCM, crossed by the first path (3), configured to apply a respective value of dispersion compensation.

Abstract: A polarization change tracking apparatus, a processing apparatus for a received signal and methods thereof. The polarization change tracking method includes: estimating a polarization change speed in a link according to a received signal; setting a response coefficient of polarization tracking according to a relationship between an estimated polarization change speed and a predetermined value, to make a response of polarization tracking and a response of adaptive equalization be consecutive; and performing compensation for polarization change on the received signal according to a set response coefficient of polarization tracking.

Abstract: A detector coherent-receives a signal being transmitted from a transmitter. A filter group includes a plurality of filters connected in series along a signal path of a reception signal. The plurality of filters include a plurality of non-linear distortion compensation filters and one or more linear distortion compensation filters. A coefficient updating unit controls a filter coefficient of the plurality of non-linear distortion compensation filters and a filter coefficient of at least some of the linear distortion compensation filters. The coefficient updating unit adaptively controls the filter coefficient, by using an error back propagation method, based on a difference between an output signal being output from the filter group and a predetermined value of the output signal.

Abstract: A stretching fiber module that stretches a pulse width of the broadband pulsed light from a broadband pulsed light source such that a time and a wavelength in a pulse correspond to each other on a one-to-one basis includes a multicore fiber and single-core compensation fibers coupled to cores of the multicore fiber. The compensation fibers compensate for a variation in wavelength dispersion characteristic between the cores of the multicore fiber and are temperature-controlled by a temperature adjuster.

Abstract: A transmission device includes: a memory; and a processor coupled to the memory and configured to: transmit or receive an optical signal; filter an electrical electric field signal that indicates electric field information of the optical signal; calculate a transmission characteristic of filtering of the electric field signal and set the transmission characteristic in the filter on a basis of a narrowing amount of a wavelength band of the optical signal transmitted through a transmission line and a narrowing amount of the wavelength band when a state of the transmission line is changed on a basis of transmission line information regarding the transmission line of the optical signal; and set a transmission parameter of the optical signal according to quality of the electric field signal filtered by the filter.

Abstract: A method to determine the types of optical fibers forming a link of an optical communication network. By scanning a signal's bit error rate at a receiver end, as a function of a pre-dispersion applied to a signal at a transmitter end, local minimums in the curve indicate the presence of amplifiers, and therefore fiber span extremities. By determining the accumulated dispersion at each fiber extremity, a ratio of dispersion per span length can be obtained and the span's coefficient of chromatic dispersion be inferred, thereby identifying the type of fiber. Alternatively, a signal's signal-to-noise ratio can be scanned, instead of its bit error rate. In a typical network, the required instrumentation is pre-existing.

Abstract: Techniques are described for providing a hybrid compensation of chromatic dispersion in optical networks to reduce power consumption by coherent receivers. In some examples, a controller may receive a chromatic dispersion value of an optical signal from a coherent receiver integrated with a receiver optical network device. The controller may compare the chromatic dispersion value with a threshold. The controller may, in response to determining that the chromatic dispersion value satisfies the threshold, perform at least one of: configure a switch connected to a dispersion compensation module (DCM) with a state to provide access to the DCM to compensate the chromatic dispersion value of the optical signal, or adjust a phase response of a filter of a coherent transmitter to compensate the chromatic dispersion value of the optical signal.

Abstract: An optical assembly for a digital projector includes a lens and a field bias optical element. The lens is disposed to receive display light generated by a display and to direct the display light along an optical path. The lens is configured to provide a first field-of-view. The field bias optical element is disposed between the lens and an aperture stop of the optical assembly. The field bias optical element is configured to bias the display light in at least one direction to provide a second field-of-view that is greater than the first field-of-view.

Abstract: The disclosed systems and methods for optical filter fault localization. The optical filter fault localization is based on: i) determining an accumulated noise density at frequencies where ASE noise is filtered out by a faulty optical filter in an optical signal; ii) comparing the accumulated noise density with predicted accumulated noise densities, the predicted accumulated noise densities representing noises predicted from a plurality of optical filters to a receiver; and iii) determining, based on the comparison of the accumulated noise density and the predicted accumulated noise densities, a location of the faulty optical filter.

Abstract: A coherent receiver comprising: a signal port receiving the signal light that has two polarization components at right angles each other; a polarization dependent beam splitter (PBS) that splits the signal light into two portions depending on the polarizations contained in the signal light; a beam splitter (BS) that splits the local light into two portions; a multi-mode interference (MMI) device that interferes between one of the two portions of the signal light and one of the two portions of the local light; optical components provided between the PBS and the MMI device; and wherein the PBS splitting a first wavelength range of the signal light and a second wavelength range outside the first wavelength range.

Abstract: A light detection and ranging (LIDAR) pixel includes a polarization controller, a grating coupler, and an optical mixer. The polarization controller includes a phase shifter that sets a phase of light in a first arm of the polarization controller and a second arm of the polarization controller.

Abstract: An optical receiving device that divides receive signals obtained by receiving an optical signal using a coherent detection scheme into a plurality of frequency bands, matches timing of the receive signals along a time axis between the frequency bands resulting from the division, performs a combining process of combining the receive signals contained in the plurality of frequency bands, and compensates the receive signals for waveform distortion either before or after the combining process, includes: a first wavelength dispersion compensation unit adapted to compensate the receive signals for waveform distortion in each of the frequency bands resulting from the division; a first nonlinear compensation unit adapted to compensate the receive signals belonging to each of the frequency bands and timed with each other in a time domain for a nonlinear optical effect; and a second wavelength dispersion compensation unit adapted to compensate the receive signals belonging to each of the frequency bands and compensate

Abstract: A wavelength conversion device includes a wavelength converter converts a wavelength band of a wavelength-division multiplex signal, a first wavelength filter transmits the wavelength-division multiplex signal on an input side of the wavelength converter, a second wavelength filter transmits the wavelength-division multiplex signal on an output side of the wavelength converter, and a controller controls a temperature of the wavelength converter such that a difference between a ratio of power of the wavelength-division multiplex signal which is not transmitted through the first wavelength filter on the input side to power of the wavelength-division multiplex signal which have been transmitted through the first wavelength filter on the input side and a ratio of a power of the wavelength-division multiplex signal which is not transmitted through the second wavelength filter on the output side to power of the wavelength-division multiplex signal which have been transmitted through the second wavelength filter.

Abstract: A transmission system formed by connecting sites through an optical fiber stores at least unique information of the transmission functional devices for each site, connection information, and information of wavelength resources that can be accommodated in the optical fiber in a facility DB as DB information D2. When the number of wavelengths of order information for requesting the number of wavelengths required for transmission of optical signals between sites is larger than the number of wavelengths that can be accommodated in the optical fiber of the DB information D2, the number of wavelengths for each of the transmission functional devices required for enabling the number of wavelengths of the order information D1 to be accommodated in the optical fiber is designed using the design unit. Designed numbers of wavelengths are configured in the corresponding transmission functional devices using the configuration unit.

Abstract: A reception apparatus includes a dispersion compensation unit configured to acquire an electrical signal resulting from conversion of an optical signal and perform, on the electrical signal, dispersion compensation with a predetermined compensation amount, a clip rate measurement unit configured to measure a clip rate for the electrical signal subjected to the dispersion compensation, and a control unit configured to detect the compensation amount that minimizes the clip rate.

Abstract: Embodiments of this application provide a clock phase recovery apparatus and method, and a chip. The clock phase recovery apparatus includes an ADC, a dispersion compensation unit, a digital interpolator, a MIMO equalization unit, and a clock offset phase obtaining unit. The ADC is connected to the dispersion compensation unit, and the dispersion compensation unit is connected to a first input end of the digital interpolator. An output end of the digital interpolator is connected to an input end of the MIMO equalization unit, and an output end of the MIMO equalization unit is connected to an input end of the clock offset phase obtaining unit. The digital interpolator is configured to adjust, based on first offset phase information output by the clock offset phase obtaining unit, a dispersion-compensated signal output by the dispersion compensation unit.

Abstract: A device (10;150;200) is configured to receive an optical signal. The device comprises a dispersion compensator (210a) comprising a plurality of optical dispersion compensator units (220). Each optical dispersion compensator unit comprises a plurality of delay elements (20;40). The dispersion compensator (210a) is configured to selectively activate one or more of the optical dispersion compensator units (220). The dispersion compensator (210a) is configured to compensate for dispersion of the optical signal with the activated one or more optical dispersion compensator unit (200).

Abstract: [Problem] A signal distortion generated when a multi-level modulated optical signal is transmitted through an optical transmission path where optical amplifiers are scattered is suppressed and transmission quality is improved. [Solution] An optical transmission system 20 includes Tx 21a to Tx 21n configured to transmit a multi-level modulated optical signal 32 to an optical fiber 25, optical amplifiers 26a to 26f configured to amplify the optical signal 32 transmitted through the optical fiber 25, the optical amplifiers 26a to 26f being scattered on the optical fiber 25, and Rx 24a to Rx 24n configured to receive the amplified optical signal 32 via the optical fiber 25.

Abstract: The present invention provides an optical transmission device, a transmission system, and a control method for a transmission system which make it possible to adjust the wavelength band of dummy light according to the wavelength band of an added main signal. This optical transmission device comprises: an output branching unit which multiplexes and outputs an added main signal and dummy light; a wavelength adjustment unit which adjusts the wavelength band of the dummy light; a signal detection unit to which an optical signal outputted by the output branching unit is inputted, and which detects the wavelength band of the added main signal and outputs a detection result; and a control unit which controls the wavelength adjustment unit according to the detection result from the signal detection unit.

Abstract: 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.

Abstract: A tunable optical dispersion compensator (TODC) for providing chromatic dispersion (CD) compensation of optical signals in a plurality of optical channels comprises: a plurality of CD compensation fibers; a tunable optical switch configurable for directing an optical signal in any of the plurality of optical channels to one of the plurality of fibers, dependent on a central wavelength of the optical signal; a first switch configurable for directing all signals in the plurality of optical channels to a first CD compensation fiber, in a first mode of operation, and for bypassing the first CD compensation fiber in a second mode of operation; and, the first CD compensation fiber, wherein the first switch and the tunable optical switch are connected so as to enable combining CD compensation provided by the first CD compensation fiber and CD compensation provided by any one of the plurality of CD compensation fibers.

Abstract: A computer-implemented method for receipt management includes receiving, using a mobile wallet stored on a mobile device of a user, receipts that include a record of transactions between the user and one or more merchants, the transactions being performed using the mobile wallet account of the user. The method includes receiving receipts for transactions that were not performed using the mobile wallet account of the user, the receipts being received from a user e-mail address, the receipts for non-mobile wallet transactions being received by the mobile wallet of the user. The method includes aggregating the mobile wallet receipts with the receipts of non-mobile wallet transactions and retrieving and displaying one or more of the mobile wallet receipts and the receipts of non-mobile wallet transactions.

Abstract: Short-term optical recovery systems and methods in coherent optical receivers minimize recovery time for fault scenarios and signal reacquisition while maintaining robust signal acquisition. The short-term optical recovery systems and methods include special techniques and algorithms to minimize recovery time, making coherent systems similar in time as conventional direct detection recovery. The short-term optical recovery systems and methods include an expedited acquisition engine that includes a reference clock recovery, a compensator to remove chromatic dispersion, a burst framer, and a compensator to remove polarization dispersion. Importantly, the expedited acquisition engine uses a memory oriented architecture to allow some properties of the acquisition engine to be stored during initial acquisition and, hence, later on be deployed in any fault scenario to expedite further recovery of a signal.

Abstract: Described are various configurations of reduced crosstalk optical switches. Various embodiments can reduce or entirely eliminate crosstalk using a coupler that has a power-splitting ratio that compensates for amplitude imbalance caused by phase modulator attenuation. Some embodiments implement a plurality of phase modulators and couplers as part of a dilated switch network to increase overall bandwidth and further reduce potential for crosstalk.

Abstract: A transmitter generates a burst signal obtained by multiplexing signals of a first polarization and a second polarization orthogonal to each other, and including, at the beginning thereof, a pilot sequence in which the first and the second polarizations each have single frequency components of a first frequency and a second frequency different from each other. A coherent light reception unit performs conversion into an electrical signal by allowing received light and local light to interfere with each other. A pilot sequence detection unit detects a pilot sequence from the converted electrical signal. The polarization estimation unit estimates polarization states of the first polarization and the second polarization at a receiver from frequency components corresponding to the first frequency, and the second frequency. An equalizer demultiplexes the first polarization and the second polarization on the basis of the estimated polarization states.

Abstract: A signal output circuit includes: a driver circuit including a variable current source and configured to output a multilevel signal; a replica circuit having a circuit configuration equivalent to the driver circuit; and a control circuit configured to control a characteristic of the driver circuit, based on an output signal of the replica circuit, wherein the replica circuit includes: a first replica circuit part configured to output first output signals having signal levels of a first subset of a plurality of signal levels corresponding to the multilevel signal; and a second replica circuit part configured to output second output signals having signal levels of a second subset of the plurality of signal levels, and the control circuit is configured to control a characteristic of the variable current source, based the first output signals and the second output signals.

Abstract: An optical signal transmission apparatus and a method are provided. The apparatus may include a set of optical transmitters, each optical transmitter configured for transmission of light signals at one or more wavelengths of light. The apparatus may include an output port configured for transmission of the light signals through a span of optical fiber. The apparatus may use an input port configured to receive other transmissions of light signals through the span of optical fiber. The apparatus may include a set of light detectors, each light detector configured to detect a time delay or phase characteristic associated with the one or more wavelengths of light. The apparatus may include a processor configured to determine a metric based on the detected time delay or phase characteristic.

Abstract: A receiver is configured to calculate a representation of a received signal conveying symbols at a frequency fS, the representation comprising non-zero components at frequencies of magnitudes exceeding fS/2. The receiver calculates a first term comprising a function of a phase difference between the representation at a first pair of frequencies separated by a gap ? and comprised within a first band of width 2? centered at fS/2, and a second term comprising a function of a phase difference between the representation at a second pair of frequencies separated by the gap ? and comprised within a second band of width 2? centered at ?fS/2, wherein ?<2?, and wherein the higher frequency of the first pair and the higher frequency of the second pair are separated by the frequency fS. An estimate of chromatic dispersion in the received signal is calculated based on the first term and the second term.

Abstract: A mobile device is configured to receive a first receipt pertaining to a first mobile wallet transaction of a user, the first receipt being a digital receipt and receive information pertaining to a plurality of transactions of the user. The mobile device is also configured to capture an image of a second receipt pertaining to the second mobile wallet transaction of the user, the second receipt being a physical receipt. The mobile device is also configured to generate an image of the first receipt of the use and extract identifying information regarding the first and second mobile wallet transactions from the first and second images, identify the first and second mobile wallet transactions within the plurality of transactions based on information extracted from the images of the first and second receipts, and associate the images of the first and second receipts with the first and second mobile wallet transactions.

Abstract: An optical modulation apparatus that can adjust modulation timing. A timing adjuster adjusts the modulation timing on the basis of an intensity detected by a light intensity detector, after a data generator respectively generates, as a first data signal and a second data signal, a first test data signal and a second test data signal each having a data string containing a test pattern in which a plurality of continuous marks and a plurality of continuous spaces are alternately repeated, and after a phase adjuster adjusts a phase difference to zero or ?.

Abstract: The technology disclosed in this patent document can be implemented to provide an analog front part of an optical receiver module for coherent optical detection where the optical receiver module receives the optical input from a fiber link, performs optical to electrical conversion and analog processing for carrier frequency compensation, optical phase noise compensation and polarization rotation, and generates an analog electrical output for subsequent signal processing for coherent optical detection. The analog processing for the polarization rotation is placed downstream from the analog processing for carrier frequency compensation, and in some implementations, downstream from the analog processing for optical phase noise compensation.

Abstract: An estimating apparatus for bias drift of a transmitting end modulator, a compensating apparatus, a receiver and a method are disclosed. Estimation and compensation of the bias drift are performed directly at the receiving end according to phase recovered received signals, with no need of providing an extra bias control circuit at the transmitting end. Estimating and compensating for the bias drift includes recovering received signals by removing a frequency difference and a phase difference between a transmitting end laser and a receiving end laser producing phase recovered received signals, estimating the bias drift of the transmitting end modulator according to the phase recovered received signals and compensating the bias drift of the transmitting end modulator in a receiver.

Abstract: There is provided a transmission apparatus including a transmitter configured to modulate a signal to a first signal having a first wavelength and a signal to a second signal having a second wavelength, and transmit the first signal and the second signal to a transmission line so that the second signal is varied in accordance with variation in an amount of cross phase modulation of the first signal passing through each position on the transmission line, and a signal processor configured to include at least one of a logic device and a processor, and configured to add an amount of chromatic dispersion at which a remaining amount of chromatic dispersion of the first wavelength at a certain position on the transmission line is equal to zero to the first wavelength in the transmission of the first signal and the second signal.

Abstract: Embodiments of the present disclosure may relate to a transceiver to transmit and receive concurrently radio frequency (RF) signals via a dielectric waveguide. In embodiments, the transceiver may include a transmitter to transmit to a paired transceiver a channelized radio frequency (RF) transmit signal via the dielectric waveguide. A receiver may receive from the paired transceiver a channelized RF receive signal via the dielectric waveguide. In embodiments, the channelized RF receive signal may include an echo of the channelized RF transmit signal. The transceiver may further include an echo suppression circuit to suppress from the channelized RF receive signal the echo of the channelized RF transmit signal. In some embodiments, the channelized RF transmit signal and the channelized RF receive signal may be within a frequency range of approximately 30 gigahertz (GHz) to approximately 1 terahertz (THz), and the transceiver may provide full-duplex millimeter-wave communication.

Abstract: An optical device includes an array of unit optical elements. Each of the unit optical elements includes a plurality of amplitude adjustment (AA) elements, each of the plurality of AA elements configured for processing one of different phases of an optical signal; an optical antenna, and a combining mechanism for optically coupling the plurality of AA elements to the optical antenna. The optical device also includes a controller coupled to the plurality of AA elements, the controller configured for generating control signals for the plurality of AA elements according to a target optical beam pattern.

Abstract: Aspects of the subject disclosure may include, a system for receiving first electromagnetic waves that propagate along a physical transmission medium. The first electromagnetic waves can convey first signals in a first frequency range and second signals in a second frequency range, whereby a first spectral location of the first frequency range exceeds a second spectral location of the second frequency range. The system can further perform frequency converting of the first signals in the first frequency range to a first updated frequency range, frequency converting the second signals in the second frequency range to a second updated frequency range and generating second electromagnetic waves that propagate along the physical transmission medium and that convey the first signals in the first updated frequency range and the second signals in the second updated frequency range. Other embodiments are disclosed.

Abstract: A method and apparatus for compensation of a chromatic dispersion through an optical compensation and an electronical compensation in optical communication. An optical communication method receives an optical signal, estimates a first transmission length based on a null component included in a frequency spectrum of the optical signal, optically compensates for a chromatic dispersion of the optical signal based on the first transmission length, estimates a second transmission length based on a null component included in a frequency spectrum of the compensated optical signal, and electronically compensates for a residual chromatic dispersion of the compensated optical signal based on the second transmission length.

Abstract: An optical signal transmission apparatus generates a multi-level optical signal from a multi-level electric signal. The optical signal transmission apparatus detects, based on a supervisory signal generated from an optical signal, an electric-to-optical (E/O) conversion characteristic of an E/O converter configured to convert an electric signal into an optical signal. For example, when the E/O converter generates a multi-level optical signal from a multi-level electric signal based on a bias signal, the optical signal transmission apparatus determines a correspondence relationship between the bias signal and the optical signal. The optical signal transmission apparatus adjusts a use range of intensities of the bias signal based on the determined correspondence relationship so that the E/O converter may linearly operate.

Abstract: A polarization insensitive optical phased array is provided, for LIDAR or other purposes. A polarization rotator splitter or two-dimensional grating coupler provides two components of co-polarized (e.g. TE-polarized) light. Each component can be routed to a separate optical phased array (OPA) component, and light output of one of the OPA components is rotated in polarization by use of a half wave plate. A polarization controller can receive and control the two components of co-polarized light and then passes the controlled light to the two OPA components. A single OPA component can also be used along with a controller which combines the two components of co-polarized light into a single output, passed to the single OPA component.

Abstract: Multiple receivers are comprised in a flexible coherent transceiver of a multi-span optical fiber network. Each of the multiple receivers is operative to handle communications on a respective channel. The multiple receivers measure optical characteristics. For each of the multiple receivers, the optical characteristics include optical nonlinear interactions on the respective channel, the optical nonlinear interactions being at least partially dependent from one span to another span. An optical power of a signal on each of the multiple channels is adjusted as a function of the optical characteristics.

Abstract: Aspects of the present disclosure describe fiber nonlinearity induced transmission penalties are reduced both in fibers with large polarization-mode dispersion, and in coupled-core multicore fibers (CC-MCF). In the case of coupled multi-core fibers, the requirement for modal delay is less.

Abstract: Aspects of the present disclosure describe systems, methods, and structures for passive optical add/drop multiplexing (POADM) architectures that remove the prior art requirement of an optical amplifier (i.e., repeater-less) at the POADM nodes.

Abstract: A sparse optical phased array transmitter/receiver includes, in part, a multitude of transmitting/receiving elements that are sparsely positioned. Accordingly, the transmitting/receiving elements are not uniformly distributed at equal distance intervals along a one-dimensional, two-dimensional, or a three-dimensional array. The positions of the transmitting/receiving elements may or may not conform to an ordered pattern.

Abstract: Monitoring output power levels of a carrier-effect based switching cell allows phase errors resulting from driving a PIN or PN junction of the switching cell to be dynamically compensated for. The compensation may also allow for compensating of phase errors resulting from the phase imbalance of input couplers as well as phase errors from the waveguide due to fabrication variations. By dynamically compensating for phase errors caused by the driving of the PIN or PN junction, the extinction ratio of the carrier-effect based switching cell can be increased.

Abstract: In order to provide a configuration for suppressing deterioration in the transmission quality of a signal light due to a nonlinear phenomenon in an optical fiber, a polarization dispersion adder is provided with: a polarization rotation unit which, with respect to each pulse of signal light generated by modulating a light carrier, rotates and outputs the polarization of the pulse during a period from a pulse rise start time (T0) to a pulse fall completion time (T1); and a delay addition unit which adds a delay of an amount corresponding to the rotation amount of the polarization added by the polarization rotation unit to the pulse outputted from the polarization rotation unit.

Abstract: An embodiment device includes an optical source configured to generate an optical carrier including an optical pulse train; and a modulator configured to modulate an amplitude of the optical pulse train, based on data generated by a data source, to produce a modulated optical signal.

Abstract: We disclose an optical transport system configured to reduce nonlinear signal distortions using an electronic phase rotation, the phase value of which is determined using pre-filtering, e.g., via a low-pass filter, of the digital samples representing an optical communication signal prior to applying a squaring operation to the digital samples. In some embodiments, the phase value used in the electronic phase rotation can be determined using double filtering of the digital samples that, in addition to the pre-filtering, employs post-filtering, e.g., via another low-pass filter, of the digital samples generated by the squaring operation. The electronic phase rotation can be implemented as part of a backward-propagation algorithm that, in addition to reducing the nonlinear signal distortions, provides at least partial dispersion compensation. In various embodiments, the corresponding backward-propagation module can be incorporated into the transmitter's digital signal processor (DSP) or the receiver's DSP.