Abstract: The present invention has an object to provide an uplink band allocation apparatus and an uplink band allocation method that are capable of setting an uplink band of a PON in accordance with an application. The uplink band allocation apparatus and method according to the present invention collect not only the amount of the data accumulated in an ONU but also the information of the application (application information) used on a terminal apparatus. Then, the uplink band allocation apparatus and method according to the present invention reflect, on a DBA conducted by the OLT, information of a band and a delay (band delay information) that have been calculated by an application information acquisition server from the application information and that are demanded by the application.

Abstract: A method for suppressing coherent and polarization-induced fading by simultaneous monitoring of loss and vibration is provided. By using merely common single-mode sensing fibers, the polarization diversity-based measurement method solves the conflict between ?-OTDR and COTDR in terms of polarization state. In addition, the method not only achieves a better coherent fading noise suppression effect but also enhances the capability of recognizing small loss events in the monitoring of loss parameters. Meanwhile, the method can suppress the influence of coherent fading on the phase demodulation of ?-OTDR and reconstruct a vibration signal with high fidelity in the monitoring of perturbation parameters, which can effectively reduce the error rate of external perturbation warning.

Abstract: An optical fiber holder is disclosed herein that includes at least one confinement slot for routing intermediate optical fibers within a housing of an optical assembly module, and preferably, a plurality of confinement slots for maintaining a target/nominal fiber bending radius for one or more intermediate optical fibers within the housing. Preferably, the optical fiber holder is disposed within the housing of an optical subassembly between an optical component, e.g., a TOSA arrangement and/or ROSA arrangement, and optical coupling receptacles, e.g., LC coupling receptacles, for optically coupling with external fibers for sending and/or receiving optical signals.

Abstract: A method for transmitting data via a coaxial electrical cable includes (a) converting symbols of each input data stream of a plurality of parallel input data streams from digital form to analog form, (b) individually filtering symbols of each input data stream, (c) transforming symbols of each input data stream from a first frequency-domain to a first time-domain, to generate parallel first time-domain samples, (d) converting the first time-domain samples to a serial multi-carrier signal, and (e) injecting the multi-carrier signal onto the coaxial electrical cable.

Abstract: A communication device includes a zoom lens that collects signal light.

Abstract: In order to maintain flexible system bandwidth and a flexible center frequency, without requiring a cyclic prefix or guard interval, a transmitter apparatus transmits a reference signal based on a single carrier waveform having a mixed symbol structure, in reference signal symbols using at least one of a cyclic prefix and a guard interval and transmits data based on the single carrier waveform without the cyclic prefix or the guard interval. The data may be based on input data processed using overlapping FFT windows, and an amount of overlap between the FFT windows may be configurable by the transmitter or the receiver. An apparatus receiving the downlink transmission comprising data based on a single carrier waveform may process the data based on overlapping FFT windows.

Abstract: In order to maintain flexible system bandwidth and a flexible center frequency, without requiring a cyclic prefix or guard interval, a transmitter apparatus transmits a reference signal based on a single carrier waveform having a mixed symbol structure, in reference signal symbols using at least one of a cyclic prefix and a guard interval and transmits data based on the single carrier waveform without the cyclic prefix or the guard interval. The data may be based on input data processed using overlapping FFT windows, and an amount of overlap between the FFT windows may be configurable by the transmitter or the receiver. An apparatus receiving the downlink transmission comprising data based on a single carrier waveform may process the data based on overlapping FFT windows.

Abstract: An assessment device for a lighting system, the device comprising: an input terminal which corresponds to an output terminal of a driver; an output terminal which corresponds to an input terminal of a light engine; a voltage regulator configured to provide power to the microcontroller, wherein the microcontroller is configured to sample an LED+ line voltage and an LED? line voltage with respect to a ground; and wherein the device is independent of the driver and the light engine.

Abstract: Disclosed in some examples, are optical devices, systems, and machine-readable mediums that send and receive multiple streams of data across a same optical communication path (e.g., a same fiber optic fiber) with a same wavelength using different light sources transmitting at different power levels—thereby increasing the bandwidth of each optical communication path. Each light source corresponding to each stream transmits at a same frequency and on the same optical communication path using a different power level. The receiver differentiates the data for each stream by applying one or more detection models to the photon counts observed at the receiver to determine likely bit assignments for each stream.

Abstract: An optical signal modulation circuit includes a laser (DFB), a modulator (EAM), and an operational amplifier. The laser (DFB) generates a laser to stimulate the modulator (EAM) to generate a photon-generated current (ip), a first port (a) of the modulator (EAM) is connected to a first input voltage (Vbias), a second port (b) of the modulator (EAM) is connected to an inverting input end of the operational amplifier, a non-inverting input end of the operational amplifier is connected to a second input voltage (Vin), and an output end of the operational amplifier is connected to the first port (a) of the modulator. In the modulation circuit, a photon-generated current (ip) of the EAM is fed back to the operational amplifier, to implement a linear relationship between the second input voltage (Vin) and the photon-generated current (ip) of the EAM, and obtain a linear EML transmission curve, namely, a high-linearity EML.

Abstract: A method includes placing an electronic die and a photonic die over a carrier, with a back surface of the electronic die and a front surface of the photonic die facing the carrier. The method further includes encapsulating the electronic die and the photonic die in an encapsulant, planarizing the encapsulant until an electrical connector of the electronic die and a conductive feature of the photonic die are revealed, and forming redistribution lines over the encapsulant. The redistribution lines electrically connect the electronic die to the photonic die. An optical coupler is attached to the photonic die. An optical fiber attached to the optical coupler is configured to optically couple to the photonic die.

Abstract: The present disclosure provides a pulse generation module, and an optical communication transmitter system and a non-linear equalizing method thereof, the pulse generation module includes: a mode detector that outputs a corresponding effective detection signal after detecting a preset mode, a controller that generates a corresponding selection signal according to a jump mode, and an equalizing pulse generator that generates a corresponding equalizing pulse signal according to the effective detection signal and the selection signal. A jump mode of each piece of data in a data stream is detected, and a corresponding equalizing pulse signal is generated based on the detected jump mode, to compensate for nonlinearity of a laser driving signal. Information about a rising edge and a falling edge is determined by detecting a jump mode of data, a balanced current is provided for a particular purpose, and nonlinearity of a laser is compensated by current output.

Abstract: A method and apparatus for isolating an RF signal are provided. A first RF signal is received and passed to an input of a 90 degree hybrid. An output of the 90 degree hybrid is connected to a first waveguide and a second output is connected to a second waveguide of an optical modulator. A second RF signal is received and passed to an input of a second 90 degree hybrid. An output of the second 90 degree hybrid is connected to the second waveguide and a second output is connected to the first waveguide of the optical modulator. The optical modulator is biased to produce single side band optical outputs of the RF signals. The single side band optical outputs are passed to an optical notch filter to remove one of the side band outputs. The other of the side band optical outputs is converted to an electrical signal.

Abstract: In an example, a communication module includes an optical transmitter, an optical receiver, and a periodical filter. The optical transmitter is configured to emit an outbound optical signal. The optical receiver is configured to receive an inbound optical signal. A first frequency of the outbound optical signal is offset from a second frequency of the inbound optical signal by an amount less than a channel spacing of a multiplexer/demultiplexer implemented in an optical communication system that includes the communication module. The periodical filter is positioned in optical paths of both the outbound optical signal and the inbound optical signal and has a transmission spectrum with periodic transmission peaks and troughs. The first frequency of the outbound optical signal may be aligned to one of the transmission peaks and the second frequency of the inbound optical signal may be aligned to one of the transmission troughs, or vice versa.

Abstract: Semiconductor packages are provided. The semiconductor package includes a package substrate, a photonic integrated circuit, a laser die, an electronic integrated circuit, and a first redistribution structure. The package substrate includes connectors. The photonic integrated circuit is disposed over the package substrate. The laser die is optically coupled to the photonic integrated circuit. The electronic integrated circuit is disposed over the package substrate. The first redistribution structure is disposed over the package substrate, wherein the electronic integrated circuit is electrically connected to the photonic integrated circuit through the first redistribution structure.

Abstract: A data communication system for transmitting packets over one or more optical fibers includes a transponder with a number of digital signal processors that transmit data packets on different optical channels. The transponder includes a switch that receives a data packet on an input and selects one of the digital signal processors to transmit the packet based on quality metrics for the different optical channels and/or information included in an OSI header for the data packet.

Abstract: An optical transmission device includes: an optical splitter configured to branch signal light input from a first optical network; a variable optical attenuator configured to control an attenuation amount of first branched signal light branched by the optical splitter and output the first branched signal light for a second optical network; and a controller configured to detect a modulation component of a signal superimposed on the signal light from second branched signal light branched by the optical splitter and control, based on the detected modulation component, an attenuation amount of the variable optical attenuator, so that the modulation component is suppressed.

Abstract: The method for controlling a wavelength-tunable laser comprises a first step of acquiring a driving condition of the wavelength-tunable laser for laser oscillation at a first wavelength, and a second step of calculating according to the driving condition of the first wavelength and a wavelength difference between the first wavelength and a second wavelength different from the first wavelength a control value or target value of a wavelength characteristic of the second wavelength in the wavelength detection unit, so as to calculate a driving condition for driving the wavelength-tunable laser, the second step including a step of selecting according to the wavelength difference one of etalon slopes having respective gradients identical and opposite to a gradient of an etalon slope used for controlling the first wavelength.

Abstract: Embodiments of the present invention disclose a method, a device, and a system for saving energy in optical communication. The method includes the following: sending first information to an optical communication device at a peer end through the optical module by using a first transmit optical power; receiving, through the optical module, second information that is returned by the optical communication device at the peer end after it receives the first information; and reducing, according to the first transmit optical power, and a receive optical power value and minimum receive optical power value in the received second information, the transmit optical power value of the optical module of the optical communication device to a difference value between the first transmit optical power value and the receive optical power value plus the minimum receive optical power value of the optical communication device at the peer end and a margin value.

Abstract: In a coherent optical receiver, sufficient demodulation becomes impossible and consequently receiving performance deteriorates if an interchannel skew arises, therefore, a coherent optical receiver according to an exemplary aspect of the invention includes a local light source; a 90-degree hybrid circuit; an optoelectronic converter; an analog-to-digital converter; and a digital signal processing unit, wherein the 90-degree hybrid circuit makes multiplexed signal light interfere with local light from the local light source, and outputs a plurality of optical signals separated into a plurality of signal components; the optoelectronic converter detects the optical signals and outputs detected electrical signals; the analog-to-digital converter quantizes the detected electrical signals and outputs quantized signals; and the digital signal processing unit includes a skew compensation unit for compensating a difference in propagation delay between the plurality of signal components, and a demodulation unit for dem

Abstract: A method and apparatus for isolating an RF signal are provided. A first RF signal is received and passed to an input of a 90 degree hybrid. An output of the 90 degree hybrid is connected to a first waveguide and a second output is connected to a second waveguide of an optical modulator. A second RF signal is received and passed to an input of a second 90 degree hybrid. An output of the second 90 degree hybrid is connected to the second waveguide and a second output is connected to the first waveguide of the optical modulator. The optical modulator is biased to produce single side band optical outputs of the RF signals. The single side band optical outputs are passed to an optical notch filter to remove one of the side band outputs. The other of the side band optical outputs is converted to an electrical signal.

Abstract: A system for optical communication through a structure includes a light pipe extending from one side of the structure to another. A sensor in communication with one side of the structure is capable of producing a sensor signal responsive to an environmental condition. Transmitter electronics are joined to the sensor for producing an electrical signal. A light source is joined to the transmitter electronics and to the light pipe to provide an optical signal. An optical detector receives the optical signal from the light pipe on the other side of the structure. Receiver electronics are joined to the optical detector and provide an output signal.

Abstract: There is provided a method for determining an in-band noise parameter, such as the Optical Signal-to-Noise Ratio (OSNR), on an optical signal-under-test (SUT) propagating along an optical communication link and comprising a data-carrying signal contribution of any arbitrary degree of polarization and a noise contribution. A spectral shape trace of data-carrying signal contribution in the SUT is estimated using a reference optical spectrum trace of a reference signal which comprises a data-carrying signal contribution that is spectrally representative of the data-carrying signal contribution of the SUT and a noise contribution which is at least approximately known. The data-carrying signal contribution is mathematically discriminated from said noise contribution in the SUT using the spectral shape trace and the test optical spectrum trace. The in-band noise parameter is then determined at least from the mathematically discriminated noise contribution.

Abstract: A multisection quantum dot laser (7) comprising at least first (8) and second (9) sections, each section (8, 9) comprising a semiconductor substrate (2) comprising p (3) and n type (4) layers and a quantum dot layer sandwiched therebetween; the semiconductor substrate (2) comprising a back electrical contact in electrical contact with one of the p and n type layers and a tuning electrical contact (13, 14) in electrical contact with the other of the p and n type layers; the quantum-dot layers of the first (10) and second (11) sections being portions of the same quantum dot layer (12) forming a laser cavity.

Abstract: A signal transmission device drives a light-emitting element and outputs an optical signal depending on a data signal from an electronic device. The device includes an element driving portion which supplies a driving current to the light-emitting element, wherein the driving current is obtained by superimposing a modulation current on a bias current, the modulation current being dependent on the data signal indicating emitting information of the light-emitting element. A temperature compensation portion of the device controls the bias current and the modulation current depending on the temperature so that a temperature-current characteristic of the light-emitting element is reproduced based on the voltage which is dependent on the temperature and the voltage which is independent from the temperature, thereby performing current control depending on the temperature.

Abstract: A method includes sweeping an optical frequency of an optical signal by an optical transmitter controlling an electric-field information signal corresponding to a transmitted signal, providing different polarization states for individual frequencies of the optical signal by the optical transmitter controlling a mixture of a first electric-field information signal corresponding to a first transmitted signal and a second electric-field information signal corresponding to a second transmitted signal, obtaining, for individual frequencies of the optical signal, polarization dependent characteristics corresponding to different frequencies, when the optical transmitter sweeps the frequency of the optical signal, by an optical receiver calculating a polarization-dependent characteristic of an optical transmission line between the optical transmitter and the optical receiver, based on items of received-electric-field information corresponding to the different polarization states, and obtaining statistical information

Abstract: Distortion and aliasing reduction for digital to analog conversion. Synthesis of one or more distortion terms made based on a digital signal (e.g., one or more digital codewords) is performed in accordance with digital to analog conversion. The one or more distortion terms may correspond to aliased higher-order harmonics, distortion, nonlinearities, clipping, etc. Such distortion terms may be known a priori, such as based upon particular characteristics of a given device, operational history, etc. Alternatively, such distortion terms may be determined based upon operation of a device and/or based upon an analog signal generated from the analog to conversion process. For example, frequency selective measurements made based on an analog signal generated from the digital to analog conversion may be used for determination of and/or adaptation of the one or more distortion terms. One or more DACs may be employed within various architectures operative to perform digital to analog conversion.

Abstract: An apparatus for encoding data signals includes a transmitter configured to encode and transmit a data signal over a communication channel, the transmitter including a precoder; a signal shaper configured to adjust the data signal by applying an equalization setting to the data signal, the equalization setting including an amplitude and offset and transmit the adjusted data signal to the precoder; and a processing unit. The processing unit is configured to perform: receiving channel coefficients associated with the communication channel; for each of a plurality of amplitude settings and a plurality of offset settings, calculating whether a modulo amplitude level would occur at a receiver using a modulo operation; selecting the equalization setting from the plurality of amplitude settings and the plurality of offset settings based on the calculation; and transmitting a control signal specifying the equalization setting to the signal shaper.

Abstract: After a startup of an optical transmitter, a control is started in such a way that a modulation amplitude of a driving signal of a phase modulator is set as 0, and that an operational point of a bias voltage is set as the lowest point of light transmission characteristics of the phase modulator. When the operational point of the bias voltage reaches the lowest point, the modulation amplitude of the driving signal is gradually increased from 0 to 2V?.

Abstract: An optical transmitter includes an optical modulator having first and second waveguides to modulate carrier light at each of the waveguides using a driving signal with 2*n intensity levels (n is an integer 1 or greater); and a phase shifter to cause a phase difference between a first optical signal and a second optical signal output from the first waveguide and the second waveguide, respectively. A photodetector converts a portion of a multilevel optical modulation signal acquired by combining the first optical signal and the second optical signals into an electrical signal. A monitor detects a change in an alternating current component in the detected modulation signal. A controller controls at least one of a first bias voltage and a second bias voltage being supplied to the first waveguide and the second waveguide, respectively, so as to increase the power value of the alternating current component.

Abstract: According to a first aspect of the present invention there is provided an apparatus for performing power equalization and phase correction of two signals (400). The apparatus comprises a first hybrid coupler (401) configured to operate as a power combiner, and a second hybrid coupler (402) configured to operate as a power divider, wherein the apparatus is configured to provide an output (406) of the first hybrid coupler as an input (407) to the second hybrid coupler.

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: 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: 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: Aspects of the present invention provide techniques for compensating nonlinear impairments of a signal traversing an optical communications system. A parallel array of linear convolutional filters are configured to process a selected set of samples of the signal to generate an estimate of a nonlinear interference field. The predetermined set of samples comprises a first sample and a plurality of second samples. A processor applies the estimated nonlinear interference field to the first sample to least partially compensate the nonlinear impairment.

Abstract: A characteristic compensation method includes obtaining compensation information when degradation of a transmission characteristic of an optical transmission path of a received light signal is compensated for by using digital signal processing with respect to an electric signal obtained by photoelectrically converting the light signal, calculating an compensation value for a characteristic compensation device that optically compensates for degradation of the transmission characteristic to start characteristic compensation, based on the compensation information with respect to the light signal, setting the compensation value in the characteristic compensation device, and switching a state in which compensation is done using the digital signal processing to a state in which compensation is done using the characteristic compensation device after the setting of the compensation value is completed.

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: An optical system may have an optical transmitter including a digital signal processor to receive a signal channel, add data corresponding to a pilot tone, generate a digital signal associated with the signal channel and including the pilot tone, and output the digital signal. The optical system may further have a digital-to-analog converter to convert the digital signal to an analog signal, a laser to provide an optical signal, and a modulator to receive the optical signal and the analog signal, and modulate the optical signal based on the analog signal to form a modulated optical signal. The modulated optical signal may include the pilot tone. The optical system may also have an optical receiver to receive the modulated optical signal, process the modulated optical signal to determine a phase associated with the pilot tone, and apply the phase to the modulated optical signal to recover the signal channel.

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: An optical modulator device directly-coupled to a driver circuit device. The optical modulator device can include a transmission line electrically coupled to an internal VDD, a first electrode electrically coupled to the transmission line, a second electrode electrically coupled to the first electrode and the transmission line. A wave guide can be operably coupled to the first and second electrodes, and a driver circuit device can be directly coupled to the transmission line and the first and second electrodes. This optical modulator and the driver circuit device can be configured without back termination.

Abstract: The present disclosure generally pertains to optical communication apparatuses having field-tunable power characteristics. In one exemplary embodiment, an optical communication apparatus has an optical transmitter. The optical transmitter is coupled to logic that receives a user input indicative of a desired transmit mode for the transmitter, and the logic then dynamically tunes the transmitter's output power according to the selected transmit mode. In addition, the optical communication apparatus may have an optical receiver for receiving optical signals. The sensitivity of the receiver is controlled by a bias voltage that is applied to the receiver by the logic. The logic is configured to receive a user input indicative of a desired receive mode and then to tune the receiver's sensitivity via the bias voltage according to the selected receive mode.

Abstract: Methods, architectures, circuits, and/or systems for monitoring operating parameters and/or generating status indications associated with electronic device operation are disclosed. The method can include (i) monitoring a first operating parameter related to operation of the electronic device to determine a first parameter value, (ii) calculating a difference between the first parameter value and a predetermined value for the first operating parameter, (iii) monitoring a second operating parameter on which thresholds for operational warnings and/or alarms are based to determine a second parameter value, (iv) updating or changing the thresholds based on a predetermined change or event in the second parameter value, (v) comparing the difference to the updated or changed thresholds, and (vi) generating a corresponding one of the operational warnings and/or alarms when the difference crosses at least one of the thresholds in a predetermined direction.

Abstract: The present disclosure relates to a differential drive circuit. The differential drive circuit generally includes a differential driver, a first transmission line coupled to a first output node of the differential driver, and a second transmission line coupled to a second output node of the differential driver. A laser diode is coupled to the first and second transmission lines. The first and second transmission lines have different delays, lengths, or impedances. In some embodiments, the delay between the first transmission line and the second transmission line is 0.2-0.4 times a rise time or fall time of a signal on either transmission line.

Abstract: An optical transmitter configured to perform digital signal equalization directed at mitigating the detrimental effects of a frequency roll-off in the transmitter's optical I-Q modulator. In various embodiments, a frequency-dependent spectral-correction function used for the digital signal equalization can be constructed to cause the spectrum of the modulated optical signal generated by the transmitter to have a desired degree of flatness in the vicinity of an optical carrier frequency and/or to at least partially mirror the frequency roll-off in the optical I-Q modulator.

Abstract: A wavelength tunable laser emission device (1) comprises: a first waveguide (31) comprising an optical amplification means for producing a stimulated light emission, the first waveguide extending in a longitudinal direction of the emission device, a second waveguide (5) made of silicon on silicon dioxide and disposed parallel to the first waveguide spaced from the first waveguide in a vertical direction of the emission device so as to allow the existence of a hybrid optical mode coupled at one and the same time to the second waveguide and to the first waveguide, the second waveguide comprising a distributed reflector (9) along the second waveguide, the second waveguide comprising transverse zones (11, 12, 13, 14) doped differently so as to form a polar junction oriented in a transverse direction of the emission device. Electrodes (15, 16) coupled to the doped transverse zones modify an effective index seen by the hybrid optical mode.

Abstract: Aspects of the invention provide transmitters and receivers for managing multiple optical signals. High order modulation, such as phase and/or amplitude modulation, is used to achieve multiple bits per symbol by transporting multiple asynchronous data streams in an optical transport system. One or more supplemental multiplexing techniques such as time division multiplexing, polarization multiplexing and sub-carrier multiplexing may be used in conjunction with the high order modulation processing. This may be done in various combinations to realize a highly spectrally efficient multi-data stream transport mechanism. The system receives a number of asynchronous signals which are unframed and synchronized, and then reframed and tagged prior to the high order modulation. Differential encoding may also be performed. Upon reception of the multiplexed optical signal, the receiver circuitry may employ either direct detection without a local oscillator or coherent detection with a local oscillator.

Abstract: The present disclosure relates to an optical transceiver for use in optical fiber communications and/or telecommunications systems and, more specifically, a low power consumption, long range pluggable transceiver. The transceiver generally comprises a photodiode with a transimpedance amplifier (PIN-TIA); an electro-absorption modulated laser (EML); an optical detector; and a directly modulated laser (DML) driving module connected between the PIN-TIA and EML laser configured to drive the EML laser. A low power-consumption DML driving module is utilized to drive the EML laser, so as to further reduce power consumption. An impedance matching circuit can be applied to modulate an electro-absorption (EA) modulator of the EML laser with maximum efficiency.

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: 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: The present invention provides a wavelength division multiplexing system and a method and device for its residual dispersion compensation, wherein the device for residual dispersion compensation of wavelength division multiplexing system comprises: a performance parameter detecting device for receiving and detecting performance parameter of receiving terminal optical signal and sending detecting result of the performance parameter to a central control device; the central control device for deciding a dispersion regulating mode of a tunable dispersion compensator according to the detecting result of the performance parameter and sending the dispersion regulating mode to a tunable dispersion compensator control device through control signaling; and the tunable dispersion compensator control device for receiving the control signaling sent by the central control device and adjusting dispersion compensation amount of the tunable dispersion compensator according to the control signaling in order to make residual di