Abstract: A multi-laser transmitter optical subassembly may include N number of lasers, where each laser is configured to generate an optical signal with a unique wavelength. The transmitter optical subassembly may further include a focusing lens and a filter assembly. The filter assembly may combine the optical signals into a combined signal that is received by the focusing lens. The filter assembly may include N?1 number of filters. Each of the filters may pass at least one of the optical signals and reflect at least one of the optical signals. The filters may be low pass filters, high pass filters, or a combination thereof.

Abstract: An optical transmission device includes an extractor that extracts respective optical signals from optical signals multiplexed from a plurality of optical signals of different wavelengths, a detector that detects wavelengths of the extracted respective optical signals, a storage that stores the wavelengths of the detected respective optical signals, and a processor that is operative to derive trends in wavelength variation of the respective optical signals based on the detected respective optical signals and the respective optical signals stored in the storage, and determines that either one or both of the extractor and the detector cause the wavelengths to be varied when the trends in wavelength variation of two or more wavelengths are the same.

Abstract: Since it is difficult to fast, simply monitor impairments of received signals with higher receiver sensitivity, a monitoring method for an optical communication system according to an exemplary aspect of the invention includes the steps of emitting lightwave signals to be modulated according to a data, forming dips at transitions between temporally consecutive groups of n symbols of the lightwave signals, wherein the dips are formed at each of (n?1) first transitions of the group, no dip is formed at the n-th transition on the lightwave signals, receiving the lightwave signals, extracting frequency components characterized by the numerical value n from received lightwave signals, and monitoring the received lightwave signals by using the frequency components.

Abstract: Methods and circuits for providing a minimum driving voltage to a current-driven load (such as a laser diode) are disclosed. The circuit and methods may be useful for efficiently providing a bias and/or driving current to the current-driven load with minimal energy loss. The circuit generally comprises (1) a driver or voltage source configured to provide the bias and/or driving current to the current-driven load, (2) a sense circuit configured to (i) sense the bias and/or driving current and (ii) convert the bias and/or driving current to a first voltage, and (3) a comparator configured to (i) receive the first voltage and first and second reference voltages and (ii) provide a feedback/error signal to the driver or voltage source, the feedback/error signal configured to maintain or adjust the bias and/or driving current at or towards a target value.

Abstract: A method for adjusting a filtering bandwidth of an optical device includes: acquiring a modulation bandwidth of a first optical signal and s modulation bandwidth of a second optical signal, where the first optical signal is an optical signal input into a first wavelength channel of an optical device, the second optical signal is an optical signal input into a second wavelength channel of the optical device, and the second wavelength channel is adjacent to the first wavelength channel; comparing the modulation bandwidth of the first optical signal with the modulation bandwidth of the second optical signal; and according to a result of comparing the modulation bandwidth of the first optical signal with the modulation bandwidth of the second optical signal, adjusting a filtering bandwidth of at least one wavelength channel of the first wavelength channel and the second wavelength channel.

Abstract: A communication system and method are described for transmitting data from a display in a bit transmission data format to a machine vision system. The described system and method allows for the process and further application of a larger amount of data faster and more reliably than by use of the human readable data from the display. A standard LCD screen displays bit transmission data corresponding to human readable data, and transmits the bit transmission data to a machine vision system, such as by use of the camera on a smart phone. The captured bit transmission data is converted into a bit data stream for further processing, such as by use of an application in the smart phone, and can be stored in memory and/or transmitted to another system to provide useful human readable information. Faster transmission of a greater amount of data is realized including, in one aspect of the bit generation, data error and correction codes.

Abstract: A collimator for a laser assembly includes a first electrostatically controllable liquid lense having a first optical axis and a second electrostatically controllable liquid lense having a second optical axis aligned with the first optical axis. A laser is provided and has such a collimator. Finally, a transmitter uses the laser for optical data transmission.

Abstract: An optical transceiver includes an optical IC coupled to a processor IC. For transmit, the optical IC can be understood as a transmitter IC including a laser device or array. For receive, the optical IC can be understood as a receiver IC including a photodetector/photodiode device or array. For a transmitter IC, the processor IC includes a driver for a laser of the transmitter IC. The driver includes an equalizer that applies high frequency gain to a signal transmitted with the laser device. For a receiver IC, the processor IC includes a front end circuit to interface with a photodetector of the receiver IC. The front end circuit includes an equalizer that applies high frequency gain to a signal received by the receiver IC. The driver can be configurable to receive a laser having either orientation: ground termination or supply termination.

Abstract: An optical module that processes an input optical signal and outputs a processed optical signal is disclosed. The optical module provides a housing and an optical processing device in the housing. The housing provides an optical input port and an optical output port in a first wall thereof in side-by-side arrangement. A third wall of the housing only provides RF terminals. Second and fourth walls of the housing provide DC terminals. Electrical connection between the DC terminals with DC pads on the device is realized through a wiring substrate whose top avoids an optical path from the optical input port to the input port of the device.

Abstract: A transmitter in an optical communications system includes a digital signal processor for processing a data signal to generate a sample stream encoding successive symbols in accordance with a constrained phase modulation scheme having a constellation of at least two symbols and a modulation phase constrained to a phase range spanning less than 4?. A digital-to-analog converter converts the sample stream into a corresponding analog drive signal. A finite range phase modulator modulates a phase of a continuous wavelength channel light in accordance with the analog drive signal, to generate a modulated channel light for transmission through the optical communications system. A receiver in the optical communications system includes an optical stage for detecting phase and amplitude of the modulated channel light and for generating a corresponding sample stream, and a digital signal processor for processing the sample stream to estimate each successive symbol of the modulated channel light.

Abstract: A current voltage conversion circuit includes first to fourth signal amplifiers; and first and second resistive passive elements, an input terminal of the first signal amplifier being connected to a terminal for inputting a current signal, one and the other terminals of the first resistive passive element being connected to output and input terminals of the first signal amplifier, respectively, an input terminal of the second signal amplifier being connected to a first connection point, input and output terminals of the third signal amplifier being connected to an output terminal of the second signal amplifier and the first connection point, respectively, an input terminal of the fourth signal amplifier being connected to a second connection point, and one and the other terminals of the second resistive passive element being connected to an output terminal of the fourth signal amplifier and the second connection point.

Abstract: An optical system has an optical emitter that transmits an optical signal through an optical fiber. An optical detector detects light from the fiber and provides an analog signal indicative of such light. A crosstalk cancellation element is configured to receive an electrical signal from the optical emitter and to adjust such signal in order to form a cancellation signal that models the optical and/or electrical crosstalk affecting the analog signal. The cancellation signal is subtracted from the analog signal thereby removing optical and/or electrical crosstalk from the analog signal.

Abstract: A method is provided for detecting the skew between parallel light signals generated from a serial data stream. The method can be used with polarization multiplexed signal, as well as with wavelength division multiplexed signals, spatial division multiplexed signals, phase modulated signals, or intensity modulated signals. The method can be used with direct detection schemes as well as with coherent detection schemes. The method is provided with: imprinting dips between a fixed number of transmitted symbols of the parallel signals; detecting an electrical signal related to the dips for each parallel signal; and comparing the electrical signals in delay.

Abstract: Systems and methods for data transport, including receiving one or more signals into a reconfigurable and flexible rate shared rate multi-transponder network architecture, wherein the network architecture includes one or more transponders with multiple line side interfaces and one or more client side interfaces. The transponders are configured to map one or more signals to multiple parallel Virtual Ethernet Links, remove idle characters from the one or more signals, buffer one or more blocks of characters using an intermediate block buffer, activate and deactivate one or more portions of input/output electrical lanes of an Ethernet module, multiplex and demultiplex the one or more signals to and from the input/output electrical lanes to enable sharing of a single optical transceiver by multiple independent signals, and insert blocks of idle characters to enable transmission over a lower rate transmission pipe.

Abstract: A method, a network, and a node each implement the transmission of Automatic Protection Switching (APS) switching coordination bytes across an OTN network. A working signal and a protection signal are received, one of which is designated as an active signal. The active signal is encapsulated in an Optical channel Data Unit (ODU) signal. APS switching coordination bytes from the working and protection signals are placed in an overhead segment of the ODU signal. The ODU signal is transmitted into and received from an Optical Transport Network (OTN) network. The working and protection signals are recreated based on the active signal encapsulated in the ODU signal and the APS switching coordination bytes in the overhead segment. The recreated working and protection signals are transmitted. In this manner, a single ODU signal may be used to transmit both the working and protection signals.

Abstract: An optical signal generation unit (110) generates an optical signal for transmission by adding modulation based on a driving signal to a carrier wave. A filtering unit (120) performs a filtering process on the driving signal. The filtering unit (120) may perform time domain equalization, and may perform frequency domain equalization. Specifically, the filtering unit (120) performs a filtering process on the driving signal, and thus sets a peak value of a power spectral density of the optical signal for transmission to be equal to or less than a second reference value while an integrated value obtained by integrating the power spectral density of the optical signal for transmission in a frequency direction is maintained at equal to or greater than a first reference value.

Abstract: Methods and apparatus for power-efficiently and reliably transmitting high-level quadrature amplitude modulation (QAM) optical signals using binary drive signals. Even though binary signals are used to drive a QAM modulator directly, without digital-to-analog conversion, the methods and apparatus disclosed allow the transmission of pilot symbol sequences having near optimal properties, such as a constant power profile in the time domain; a mean power that is approximately the same as the mean power of the data symbols; and roughly uniform amplitude in the frequency domain for non-zero frequency components of the pilot symbol sequence. The binary drive signals can be processed so that the modulated optical signals are selectively constrained to a subset of points of the QAM constellation to form a QAM constellation with reduced size and a mean power that is approximately the same as the mean power of the original QAM constellation.

Abstract: In some examples, a transmit assembly is described that may include a first optical transmitter, a second optical transmitter, and a polarizing beam combiner. The first optical transmitter may be configured to emit a first optical data signal centered at a first frequency. The second optical transmitter may be configured to emit a second optical data signal centered at a second frequency offset from the first frequency by a nominal offset n. The polarizing beam combiner may be configured to generate a dual carrier optical data signal by polarization interleaving the first optical data signal with the second optical data signal. An output of the polarizing beam combiner may be configured to be communicatively coupled via an optical transmission medium to a polarization-insensitive receive assembly.

Abstract: A communication device includes: a converting part converting a data signal from a non-return-to-zero signal to a return-to-zero signal; a trigger flip-flop inverting an output signal every time the return-to-zero signal changes in one cycle; a first filter outputting a positive pulse and a negative pulse alternately, which indicate existence and absence of the pulse corresponding to a value of the data signal, by removing a low frequency component of an output signal of the trigger flip-flop.

Abstract: In one example embodiment, a transmitter module includes a header electrically coupled to a chassis ground. First and second input nodes are configured to receive a differential data signal. A buffer stage has a first node coupled to the first input node and a second node coupled to the second input node. An amplifier stage has a fifth node coupled to a third node of the buffer stage and a sixth node coupled to a signal ground that is not coupled to the chassis ground. An optical transmitter has an eighth node coupled to a seventh node of the amplifier stage and a ninth node configured to be coupled to a voltage source. A bias circuit is configured to couple a fourth node of the buffer stage to a bias current source.

Abstract: According to a first aspect, techniques are provided to optimize a Mach-Zehnder modulator drive waveform by distorting the outer modulation levels of the waveform, thereby equalizing eye openings of the received optical field, and in particular creating a wider and more defined central eye opening of the received optical field. According to a second aspect, techniques are provided to adjust in-phase (I) modulation levels based on the imperfect performance of a Mach-Zehnder modulator allocated to modulate quadrature-phase (Q) modulation levels, and conversely to adjust the Q modulation levels based on the imperfect performance of an MZ modulator allocated to modulate I modulation levels.

Abstract: The present invention discloses a wavelength-tunable laser output method. The method includes adjusting, by a thermoelectric cooler according to a received control signal, a working temperature of a laser, so that the laser emits a multi-longitudinal mode optical signal corresponding to the current working temperature and the multi-longitudinal mode optical signal corresponds to a transmittance peak of a filter at a peak wavelength; performing, by the filter, filtering processing on the multi-longitudinal mode optical signal to obtain a single-frequency optical signal with a corresponding peak wavelength frequency; reflecting, by a reflector, a part of the single-frequency optical signal back to the laser; and locking, by the laser according to a center wavelength of the received single-frequency optical signal, an operating frequency, and generating and outputting a frequency-locking optical signal with a wavelength that is the same as the center wavelength of the single-frequency optical signal.

Abstract: A method of transmitting light is disclosed. The method comprises: transmitting a first light pulse into a medium to form in the medium a filamented region that is capable of guiding light, and transmitting a second light into the filamented region, wherein the second light is a pulsed light or continues wave light, and wherein the second light is transmitted at least 10 nanoseconds after the first light pulse.

Abstract: A vehicle powering wireless receiver for use with a first electromagnetic resonator coupled to a power supply. The wireless receiver includes a load configured to power the drive system of a vehicle using electrical power, and a second electromagnetic resonator adapted to be housed upon the vehicle and configured to be coupled to the load, at least one other electromagnetic resonator configured with the first electromagnetic resonator and the second electromagnetic resonator in an array of electromagnetic resonators to distribute power over an area, wherein the second electromagnetic resonator is configured to be wirelessly coupled to the array to provide resonant, non-radiative wireless power to the second electromagnetic resonator from the first electromagnetic resonator.

Abstract: An optical processing system for an electronic device is provided. The optical processing system includes a digital component for generating digital signals based on received signals from the electronic device. The optical processing system further includes an optical component for generating optical signals based on the digital signals. The optical processing system further includes a transmit component for transmitting the generated optical signals to an earpiece. The earpiece includes a converter for converting the optical signals into electrical signals, and a speaker for converting the electrical signals to sound.

Abstract: A method implemented in a transmission apparatus used in an optical fiber communications system for a polarization switched differential quaternary phase-shift keying (DQPSK) signal is disclosed. The method comprises splitting data into two or more data streams, inputting said two or more data streams to 1-bit DQPSK precoders to perform 1-bit DQPSK precoding, and multiplexing inphase outputs of the 1-bit DQPSK precoders to generate a first output; and multiplexing quadrature outputs of the 1-bit DQPSK precoders to generate a second output. Other methods, apparatuses, and systems also are disclosed.

Abstract: Data transmission method and apparatus utilizing color coding is disclosed. A one-to-one correspondence between a set of eight unique 3-bit data units and a set of eight unique color representations is established for color coding a sequence of 3-bit data units. Transmission of the sequence of 3-bit data units is then facilitated using a sequence of color representations, wherein each one of the sequence of 3-bit data units has a one-to-one correspondence with one of the sequence of color representations.

Abstract: A transmission device that receives a main signal, the transmission device includes: a receiver configured to receive, from a different transmission device corresponding to a source device of the main signal, a control signal including setting information concerning the main signal; a frame processing section configured to process a frame of the main signal; and a first controller configured to set the frame processing section in accordance with the setting information.

Abstract: The I phase modulator modulates a phase based on the bias voltage in which a first modulation signal and a first pilot signal are inherent and the Q phase modulator modulates a phase based on the bias voltage in which a second pilot signal different from the first pilot signal and a second modulation signal are inherent. A time-average power synchronous detection unit detects an optical power at a timing at which the positivity and negativity of the voltages of both pilot signals become the same, and an optical power when the positivity and negativity of the voltages of both pilot signals are opposite. The bias voltage control unit controls the bias voltage so that the difference between both the optical powers becomes small based on the detection result of the time-average power synchronous detection unit.

Abstract: A system includes a beacon device including a communication strip having a plurality of directed light emitters distributed along the communication strip. The beacon device can transmit a directed light signal via the directed light emitters. The system further includes a tag including a processor, a radio frequency transmitter coupled to the processor, a directed light receiver coupled to the processor, and a lens having first and second major surfaces and a side surface, the tag to receive the directed light signal via the side surface and to transmit a radio frequency tag message via the radio frequency transmitter. The system also includes a radio frequency reader to receive the radio frequency tag message.

Abstract: An optical modulator includes: a modulator including an optical waveguide provided in a semiconductor substrate having an electro-optical effect and an electrode to apply an electric field depending on a bias voltage and a modulation signal to the optical waveguide; a driver circuit to generate a modulation signal in accordance with an input signal; a superimposer to superimpose a reference signal on the bias voltage, the reference signal having lower frequency than the modulation signal; and a controller to control a bias voltage in a direction orthogonal to a modulation direction of the modulator based on the frequency component of the reference signal extracted from a modulated optical signal generated by the modulator.

Abstract: A 2n-QAM (e.g. 16-QAM) optical modulator comprising cascaded I-Q modulators. The first I-Q modulator applies 2n?2 (e.g. 4) QAM to an optical signal, having a constellation diagram with the 2n?2 (e.g., 4) constellation points located in quadrant I. The second I-Q modulator subsequently applies a quaternary phase-shift keying (QPSK) modulation scheme to the optical signal, thereby rotating the constellation points of the 2n?2-QAM modulation scheme to quadrants II, III and IV, to produce a 2n-QAM modulation constellation diagram. The rotation causes the 2n-QAM modulator to inherently apply four quadrant differential encoding to the optical signal. A method of 2n-QAM optical modulation is also provided and optical signal transmission apparatus comprising the 2n-QAM optical modulator.

Abstract: A transmission apparatus includes: a data signal processor to add first data of a control signal to a data signal received, and transmit the data signal; a first signal output module to output second data of the control signal; an update controller to control an update of a function included in the first signal output module; and a second signal output module, when receiving a notice of an instruction for updating the function from the update controller, to output the first data that is the second data held therein when the notice thereof is received, wherein the second signal output module, when receiving a notice of a completion for updating the function from the update controller, outputs the first data that is the second data received from the first signal output module updated by the update controller.

Abstract: Disclosed herein is an optical network terminal. The Optical Network Terminal (ONT) includes a laser diode for generating an optical signal to be transmitted to the OLT. A laser diode driving unit supplies driving current required for light emission of the laser diode. A driving current detection unit detects the driving current. A light emission time determination unit calculates a light emission time of the laser diode depending on a time for which the driving current is detected, and outputs a power control signal including information about results of a comparison between the light emission time of the laser diode and a preset reference time. A power supply voltage control unit interrupts a power supply voltage of the laser diode driving unit when the power control signal includes information indicating that the light emission time of the laser diode is longer than the reference time.

Abstract: In one embodiment, the optical transport system has an optical transmitter, an optical receiver, and one or more phase-sensitive amplifiers (PSAs) disposed within an optical link that connects the optical transmitter and receiver. The optical transmitter employs a first nonlinear optical process to generate a two-carrier signal in a manner that makes this signal suitable for phase-sensitive amplification. The PSAs employ a second nonlinear optical process to optically amplify the two-carrier signal in a phase-sensitive manner to counteract the attenuation imposed onto the two-carrier signal by lossy components of the optical link. The optical receiver employs a third nonlinear optical process in a manner that enables the receiver to beneficially use redundancies in the two-carrier signal, e.g., for an SNR gain.

Abstract: A subscriber-side optical network unit (ONU) includes a control LSI for outputting a data signal and a pre-bias signal at fixed intervals, an optical transmitter-receiver for producing optical output in response to these signals, and a light-emission error preventing circuit for preventing light-emission error. First and second light-emission error detecting circuits output an abnormality detection alarm signal when no rising edge occurs in the data signal and pre-bias signal for a prescribed period of time. An OR element, when receiving the abnormality detection alarm signal from at least one of the first and second light-emission error detecting circuits, supplies the optical transmitter-receiver with a shutdown signal and halts the optical output.

Abstract: An optical transmission circuit comprises a light emitting element and a differential amplifier circuit to which differential input signals are input to modulate an optical output of the light emitting element. The differential amplifier circuit includes a first current source, a first transistor, a second transistor, a third transistor, and a fourth transistor. The first current source is connected to a first potential source and the sources of the third and the fourth transistor are connected to a second potential source. The differential amplifier circuit includes a second current source having one end that is connected to a third potential and another end that is connected to a drain of the second transistor, and a fifth transistor having a gate that is connected to the gate of the fourth transistor, a source that is connected to the second potential, and a drain that is connected to the light emitting element.

Abstract: An optical modulation device includes a generating circuit that generates a low-frequency signal, an average value of amplitude as an alternating-current component of the low-frequency signal being different from a center value of the amplitude of the low-frequency signal, a superimposing unit that superimposes the low-frequency signal on a data signal, an optical modulator that modulates, using the superimposition of the low-frequency signal by the superimposing unit, light from a light source and outputs a light signal, a calculating circuit that calculates an amplitude average value and an amplitude center value of a low-frequency component obtained from the light signal output by the optical modulator, and a controller that controls a bias voltage of the optical modulator such that the amplitude average value is brought closer to the amplitude center value of the frequency component calculated by the calculating circuit.

Abstract: A miniature pluggable video module having a length less than one inch, and a width less than three quarters of an inch, and a plurality of pin connectors attached to the back of the housing. The pluggable video module can be mounted horizontally or vertically. Inputs and outputs of the module can be adapted to include various types of optical or electrical connectors. The inputs and outputs of the module can be modified into various combinations of optical or electrical configurations, and the combinations of inputs and outputs also can be modified.

Abstract: Disclosed herein are a Visual Light Communication (VLC) method and apparatus using a DMX-512 network. The VLC apparatus includes a DMX signal generation unit and a DMX signal transmission unit. The DMX signal generation unit generates VLC data packets each including a DMX header, fragmentation information, and a data fragment. The DMX signal transmission unit transmits the VLC data packets to an LED lighting apparatus coupled over a DMX-512 network in order to perform VLC.

Abstract: An optical receiver, within a first device, may receive first configuration information from an optical transmitter, also within the first device. While receiving the first configuration information, the optical receiver may operate according to a clock. Later, the optical receiver may receive optical data from a second device according to the first configuration. While receiving the optical data from the second device, the optical receiver does not operate according to the clock, wherein the optical receiver not operating according to the clock allows the optical receiver to receive the optical data with greater sensitivity.

Abstract: Systems and methods are disclosed to perform nonlinear compensation (NLC) in an optical communication system by applying digital backpropagation (DBP) using a frequency-shaped split-step Fourier method (FS-SSFM), and processing a data block using an overlap-and-save method with a block size M and an overlap factor of N samples between adjacent blocks.

Abstract: An inventive method for multi-symbol polarization switching for differential detection optical systems includes modulating a laser source by a DQPSK modulator, driving the DQPSK modulator with a data block configured for generating multi-symbol polarization-switched DQPSK differential-encoded signals, and polarizing the multi-symbol polarization-switched DQPSK signals with a polarizing modulator whose modulation speed is based on how often polarization states vary, wherein the data block provides a bits manipulation to provide the multi-symbol polarization switching thereby enabling differential detection for recovering correct original data by a receiver.

Abstract: LEDs that transmit or receive data in a VLC may create a flickering effect which is observed when the human eye is able to perceive the fluctuations of the light intensity in a LED. To prevent flickering, the LEDs may emit light based on a pattern of data and energy intervals. During the data intervals, a LED transmitting a message sends one or more data symbols to receiving LEDs. The receiving LEDs, however, are reversed bias and do not emit light. During the energy intervals, any LED in the VLC system may emit light. Each LED uses the energy interval to compensate for the light transmitted (or not transmitted) during the data interval. The combination of data and energy levels results in an observer seeing light with a constant intensity rather than changing intensity.

Abstract: A substantially 400 Gb/s optical transceiver includes a substantially 400 Gb/s optical transmitter which includes a set of four substantially 100 Gb/s tunable optical transmitters, each transmitting a substantially 100 Gb/s optical signal in a wavelength division multiplexed form over four channel wavelengths selected such that the resulting 16 channel wavelengths are different from each other and are suitable for WDM, and an optical transmission interface including a set of four 1:4 wavelength division demultiplexers which are operative to demultiplex the substantially 100 Gb/s optical signals to produce substantially 25 Gb/s optical signals over each of the 16 different channel wavelengths, and a 16:1 wavelength division multiplexer which is operative to multiplex the substantially 25 Gb/s optical signals of the 16 different channel wavelengths to generate a substantially 400 Gb/s optical signal.

Abstract: A method is provided to lower the overall power consumption of small form-factor pluggable (SFP) transceivers. The method includes receiving an indication to operate the SFP transceiver in a low power mode, and setting the SFP transceiver to a low power mode in response to the indication by at least switching off a thermal electric cooler (TEC) that controls a temperature of a laser diode of the SFP transceiver. The proposed method may be implemented whenever a reach is not more than a predetermined distance, for example, 65 kilometers. At such reduced distances, the TEC of the SFP transceiver can be switched off while still guaranteeing link functionality. The instant low power mode has the benefit of reducing the power consumption of the SFP transceiver so that, for example, host platforms with lower power delivery budgets can support the SFP transceiver for at least some applications.

Abstract: Data for transmission by an optical transmitter that is driven by a signal driver is encoded, where the encoding is according to a criterion that specifies a reduction of an aggregate electrical current of the signal driver.

Abstract: A modulator bias selection method, a coherent optical transmitter, and optical modulator solve the problem of generating a correct constellation using the bias points with the minimum phase adjustment range. The optimum modulator bias systems and methods include a coherent optical transmitter with control of four (XI, XQ, YI, YQ) quadrature data signals via a transmitter (Tx) application specific integrated circuit (ASIC), with a modulator bias controller which implements an algorithm to find the optimum bias points. The optimum bias points yield a correct constellation with minimum phase/bias adjustment. An algorithm is used to find the optimum bias solution using fast, simple method, adjusting only one quadrature at a time and exploiting a control feature of the Tx ASIC. This algorithm is significantly simpler than a generalized search, is a local algorithm, and uses only DC power measurement at the transmitter.

Abstract: There is provided an optical signal transmitting apparatus included in an optical communication system which performs communication by transmission and reception of an optical signal indicating digital data. The optical signal transmitting apparatus includes a transmission data generating unit configured to set a data length of each frame constituting the optical signal based on a frequency tolerance of a clock signal on a transmission side and a reception side, and generate digital transmission data having multiple consecutive frames of same contents, each frame having the set data length; and a light emission driving unit configured to drive a light emitting unit to output the optical signal indicating the digital transmission data.

Abstract: A system is configured to receive a block of symbols, associated with a phase-modulated signal that includes data symbols that correspond to a payload associated with the signal, and control symbols; process the control symbols to identify an amount of phase noise associated with the control symbols; reset a phase, associated with each of the data symbols, based on the amount of phase noise and a reference phase; interleave the respective data samples, of each of the data symbols with other data samples, where the interleaved respective data samples cause errors, associated with the respective data samples, to be spread out among the other data samples and reduces an error rate relative to a prior data rate that existed before the interleaving; and perform forward error correction on the interleaved respective data samples.