Abstract: Phase shift keying optical modulation apparatus comprising optical phase shifting apparatus and an optical modulator. The optical phase shifting apparatus is arranged to receive an optical carrier signal and is arranged to selectively apply a preselected optical phase shift to the optical carrier signal in dependence on a symbol of a 2N-level phase shift keying modulation format to be encoded onto the optical signal. The optical modulator is arranged to receive the optical carrier signal from the optical phase shifting apparatus and is arranged to apply a phase modulation to the optical carrier signal in dependence on the symbol, to thereby encode the symbol onto the optical carrier signal. The phase modulation is a phase-modulation of an N-level phase shift keying modulation format.

Abstract: A determination device for a wavelength division multiplex communication system, configured to set each of different paths each of which is formed by connection of spans each of which is a zone between two adjacent transmission devices, among transmission devices forming a communication network, in the communication network, or a single span in the communication network, for the corresponding one of different wavelengths, and configured to transmit an optical signal of each of the wavelengths via the corresponding path set to the wavelength, the device includes: a determination section configured to determine whether an optical signal of at least one of the wavelengths is transmittable only to a path, among newly formed paths, for which the number of spans forming the path is equal to or less than a predetermined upper-limit number, in order to transmit one or more optical signals of one or more wavelengths among the wavelengths.

Abstract: This spatial division multiplexing (SDM) in power-limited optical communication systems. In general, an SDM optical transmission system may be configured to increase data capacity over the data capacity of a non-SDM optical transmission system while maintaining power consumption at or below that of the existing non-SDM optical transmission system. To realize such an improvement in performance without increasing power consumption, an example SDM optical transmission may be constructed by reducing system bandwidth, reducing and/or altering equipment for filtering, reducing optical amplifier spacing, reducing operational amplifier power consumption, etc. In this manner, increased data transmission performance may be realized even where available power may be strictly limited.

Abstract: Provided is a station-side apparatus configured to conduct optical communication with a plurality of subscriber apparatuses via a plurality of wavelengths. The station-side apparatus includes a storage apparatus, management information stored in the storage apparatus and configured to indicate whether or not a subscriber apparatus is a first apparatus whose wavelength used for communication is changed to another wavelength, and a transmission unit configured to transmit downlink frames addressed to the plurality of subscriber apparatuses in an order of transmission determined based on the management information.

Abstract: An Optical Line Termination (OLT) is connected to an Optical Network Unit (ONU) over an Optical Distribution Network (ODN), wherein the OLT transmits multiple time domains to the ONU over the ODN for synchronizing client equipment connected to the ONU with different time domains. The multiple time domains are transported in one or more OMCI messages, and each OMCI message comprises a single Managed Entity.

Abstract: A signature encoded light system includes at least one light source. The at least one light source is configured to output a first encoded light signature embedded within light in the visible spectrum. A light signature detection device is configured to receive a composite light signal formed with light from the at least one light source and ambient light. The light signature detection device is configured to identify the first encoded light signature.

Abstract: According to one embodiment of the present disclosure, a current-mode driver with built-in CTLE provides signal correction for a transmitter. The current-mode driver includes a digital current source operable to use a data signal to produce a main current signal. The current-mode driver also includes a filtering circuit comprising a resistor and a capacitor. The filtering circuit is operable to receive a negative data signal and produce a filtered data signal. The filtering circuit may be tuned to produce a zero at a pole frequency in the filtered data signal that compensates for signal degradation caused by the optical transmitter. The current-mode driver also includes an analog current source coupled in parallel to the digital current source, wherein the analog current source is operable to generate a subtraction current signal proportional to the filtered data signal. The subtraction current signal combined with the main current signal are operable to drive the transmitter.

Abstract: Systems and methods described herein include methods and systems for controlling bias voltage provided to an optical modulating device. The optical modulating device is biased at a bias point that is different from a null point of the device such that an offset to the received optical power due to limited extinction ratio is reduced.

Abstract: Distributed communications systems providing and supporting radio frequency (RF) communication services and digital data services, and related components and methods are disclosed. The RF communication services can be distributed over optical fiber to client devices, such as remote units for example. Power can also be distributed over electrical medium that is provided to distribute digital data services, if desired, to provide power to remote communications devices and/or client devices coupled to the remote communications devices for operation. In this manner, as an example, the same electrical medium used to transport digital data signals in the distributed antenna system can also be employed to provide power to the remote communications devices and/or client devices coupled to the remote communications devices.

Abstract: An apparatus, a method and a computer program for determining estimates is disclosed. The apparatus determines estimates for transmitted symbols from received symbols of an optical signal affected by cross-Polarization Modulation (XpolM). The apparatus groups two or more subsequent received symbols from the optical signal into a group of received symbols and estimates an optical channel based on the group of received symbols and a hypothesis on the transmitted symbols. The apparatus further determines a reliability measure for a combination of the group of received symbols, the channel estimate, and the hypothesis, and determines the estimates for the transmitted symbols based on reliability measures for multiple hypotheses on the transmitted symbols.

Abstract: An arrayed waveguide grating (AWG) based interconnection network and modular construction method, comprising N1 left nodes, with each left node having N2 ports, N2 right nodes, with each right node having N1 ports, where N1?N2, N1 and N2 having a greatest common divisor r, and each port having an optical transceiver associated with a fixed wavelength; N1n2 r×1 wavelength multiplexers having their input ports respectively connected with the ports of N1 left nodes, where n2=N2/r; N2n1 1×r wavelength demultiplexers having their output ports respectively connected with the ports of N2 right nodes, where n1=N1/r; n1n2 r×r AWGs connecting the r×1 wavelength multiplexers and the 1×r wavelength demultiplexers r×rn1n2, and each of the r×r AWGs being associated with a wavelength subset {?k|k=0, 1, . . . , r?1}.

Abstract: An optical power supply includes a plurality of lasers each providing an output at a respective optical wavelength and optical power and a plurality of optical splitter groups, each comprising an input associated with a respective one of the plurality of lasers and splitting the input into a plurality of outputs each having an output power approximated by Power n = 1 x n ? Power input , where: x is an integer greater than 1; n is a number of the outputs of the optical splitter group and n=1 . . . m; m is a total number of outputs of the optical splitter group; Powern is the output power of the nth output; and Powerinput is the optical power of the output of the laser received at the input of the optical splitter group.

Abstract: An optical network including: a medium; at least one beam of optical waveguides extending over the medium; for each beam, interfaces between the beam and the processing units, respectively. The beam successively links the interfaces in a closed loop oriented in a certain direction of rotation of information. The communication units of each interface are transversely arranged in ranks increasing from the periphery to the interior of the beam. First and second optical waveguides start from different interfaces or end at different interfaces. The first optical waveguide links two communication units both of them readers and/or writers of different ranks in first and second respective interfaces. The second optical waveguide passes through a communication unit from the second interface of lower rank to that of the communication unit of said second interface through which the first optical waveguide passes.

Abstract: An optical transmitter determines the transfer function in the reference-based pre-equalization for applying to an optically modulated signal at the transmitter. The determined pre-equalization transfer function is made robust to linewidth inaccuracy of the optical source by performing phase correction during the calculation of the pre-equalization transfer function. The phase correction includes averaging a number of consecutive received phase samples. The determined pre-equalization transfer function is applied to modulated signals prior to the transmission over an optical medium.

Abstract: An optical receiver includes a semiconductor optical amplifier configured to amplify wavelength multiplexed light, an optical demultiplexer configured to demultiplex the wavelength multiplexed light amplified by the semiconductor optical amplifier into light of a plurality of signals having different wavelengths, a plurality of light-receiving elements configured to receive the signal light obtained by demultiplexing of the optical demultiplexer, a detector configured to detect an intensity of the wavelength multiplexed light of a previous stage of the optical demultiplexer, a memory configured to store an upper limit value of a drive current of the semiconductor optical amplifier corresponding to a detection result of the detector, and a controlling the drive current of the semiconductor optical amplifier by referring an output of the detector and the upper limit value.

Abstract: An apparatus comprising a receiver configured to couple to an Ethernet Passive Optical network over Coaxial (EPoC) network, and receive an upstream Orthogonal Frequency Division Multiplexing (OFDM) signal comprising a plurality of OFDM Resource Elements (REs), and a processor coupled to the receiver and configured to determine a presence of a burst marker sequence in the received signal, wherein the burst marker sequence comprises interlaced pilot symbols and null symbols, and wherein determining the presence of the burst marker sequence comprises computing a power ratio between a first set of the OFDM REs and a second set of the OFDM REs, and determining that the burst marker sequence is found when the computed power ratio exceeds a pre-determined threshold.

Abstract: A method of transmitting a data signal in an optical communications system. The method includes processing the data signal to generate an analog drive signal, wherein the processing comprises applying a first non-linear operation such that frequency components of the drive signal lay in at least two separated spectral bands. An optical carrier light is modulated using the analog drive signal.

Abstract: Provided are a signal transmission method and apparatus. In the signal transmission method, a terminal device obtains a signal to be sent; and the terminal device sends the signal through a visible light medium, wherein after being demodulated, the signal sent through the visible light medium is carried on a power line for transmission. By virtue of the solution, the problem in related technologies regarding the integration of the visible light communication as a wireless access manner with the power line communication technology is solved, the construction of the communication network can be more convenient and faster, and the advantages of the visible light communication and the power line communication technology are fully utilized.

Abstract: A pulsed light communication device has a plurality of indicator light emitting diodes emitting diodes emitting at least one of a plurality of wavelengths of colored light to correspond to a designated color assigned to a security level for a network. A continuous uninterrupted modulated pulsed light emitting diode light signal may be generated having a sensitivity threshold detection level exceeding minimal parameters of a photodetector.

Abstract: A high-speed optical receiver implemented using a low-speed light receiving element is provided, which is configured to receive an optical signal having a higher transmission rate than that received using a general avalanche photo diode (APD) by expanding a frequency bandwidth using a receiver circuit configured together with an APD in the optical receiver including the APD, an APD bias control circuit, a transimpedance amplifier (TIA) for amplifying a signal received from the APD to have low noise, and a post amplifier; and a method of implementing such a high-speed optical receiver.