Abstract: Systems and methods for data transport are provided which encode streams of data using low density parity check (LDPC) encoders and map data streams to symbols, by assigning bits of symbols to a signal constellation and associating bits with constellation points. Constellation points are generated using a D-dimensional optimum signal constellation design (OSCD) method. The OSCD determines an optimum source distribution for an optical channel, generates D-dimensional training sequences from the optimum source distribution, determines new signal constellation points as the center of mass for each D-dimensional cluster of points, and repeats these steps until convergence or until a predetermined number of iterations is reached.

Abstract: Systems and methods can operate to detect and avoid optical beat interference (OBI) in broadband devices by use of restrictive channel assignment. An OBI-mitigating mapper algorithm can leash OBI candidates in a circular queue to avoid scheduling service flows likely to result in OBI generation. In some implementations, the algorithm can automatically leash all pre-DOCSIS 3.0 service flows. In alternative implementations, the algorithm can allow the CMTS to normally load balance pre-DOCSIS 3.0 devices while manually adding and/or removing pre-DOCSIS 3.0 service flows from the OBI candidate queue based upon lost transmissions or a designated age-out timer.

Abstract: A long haul transmission system uses a digital signal processor DSP instead of an additional optical phase conjugate copier because the optical phase conjugate copier requires high quality optical carrier regeneration to recover the pump and optical PLL to maintain phase matching between signal and pump. Therefore, the use of DSP to process the signal and idler at receiver end greatly simplifies the system setup, increases the system stability and decreases the system cost.

Abstract: An optical transmission system including a transmitting unit to transmit an optical main signal, a receiving unit to receive the optical main signal, and a transmission line through which the optical main signal is transmitted, the optical transmission system includes: an optical transmitter unit configured to be activated or inactivated based on a control signal so as to transmit the control signal, the optical transmitter being included in the transmitting; and an optical receiver configured to receive light with the activate state or the inactivate state of the optical transmitter the optical receiver being included in the receiving unit, wherein the receiving unit regenerates the control signal, based on a power of the received light.

Abstract: The present invention discloses a device and method for controlling a lasing wavelength of a tunable laser, and a wavelength division multiplexed-passive optical network having the same. In a device and method for controlling a lasing wavelength of a tunable laser, and a wavelength division multiplexed-passive optical network having the same, it is possible to improve performance of the wavelength division multiplexed-passive optical network by automatically controlling a lasing wavelength of a tunable laser to be matched with a transmission wavelength of a wavelength division multiplexer/de-multiplexer using optical power or optical beating components obtained by a reflected optical component which is Raleigh backscattered or reflected, and is generated on an optical fiber.

Abstract: Techniques are presented for automatic tuning of operating parameters, e.g., amplifier gain, in an optical network. A section of an optical network comprises a plurality of spans between optical nodes, and each optical node has an amplifier to amplify optical signals for transmission between optical nodes. Physical network layer data is obtained from the optical nodes for use as input to an analytical model. A set of powers defining an optimum working point of the amplifiers is computed based on variations in amplifier noise figure which depend on amplifier gain. A figure of merit representative of network section performance is computed based on linear and non-linear noise at current power levels of the amplifiers. The figure of merit is evaluated. The set of powers is applied to the amplifiers in the network section when evaluation of the figure of merit indicates that network performance improvement can be achieved.

Abstract: The disclosure provides a method and system for realizing power saving mechanism management between an Optical Network Unit (ONU) and an Optical Line Terminal (OLT). The method includes: passing power saving information between the ONU and the OLT through an extended Operation Administration and Maintenance (OAM) frame; closing/opening an optical module of the ONU based on the obtained power saving information. With the method of the disclosure, the optical module is closed in time when the optical module of the ONU is not needed, thus reducing power consumption of the ONU, and enabling interaction between the ONU and the OLT to meet the requirement for power saving and emission reduction.

Abstract: An optical cross-connect apparatus includes: a plurality of optical cross-connect portions each having an inter-node connection input port and an inter-node connection output port respectively connected to each of the plurality of the inter-node connection optical fibers, an internal connection input port, and an internal connection output port, wherein for each of the plurality of the optical cross-connect portions, the internal connection output port of a predetermined optical cross-connect portion is directly connected to the internal connection input port of another optical cross-connect portion, or the internal connection output port of a predetermined optical cross-connect portion is directly connected to the internal connection input port of another optical cross-connect portion and is indirectly connected via the another optical cross-connect portion to the internal connection input port of yet another optical cross-connect portion.

Abstract: A monitoring apparatus for detecting uncharacteristic short-term power level changes of an optical signal transmitted through an optical fiber, said monitoring apparatus comprising a power level variance calculation unit adapted to calculate a power level variance on the basis of a long-term power level and a current power level of said optical signal and a short-term variance filter adapted to filter transient changes indicated by the calculated power level variance and to generate a trouble occurrence indication indicating an uncharacteristic short-term power level change, if the filtered power level variance exceeds a predetermined power level variance.

Abstract: According to an aspect of an embodiment, a method of spectrum defragmentation in an optical network may include assigning an optical signal within an optical network to a first frequency slot that spans a first portion of an optical spectrum of the optical network. The method may also include constructing a frequency slot dependency map based on the assignation of the optical signal to the frequency slot. The method may also include reassigning, as a result of an optical signal departure event, the optical signal to a second frequency slot based on the frequency slot dependency map. The second frequency slot may span a second portion of the optical spectrum of the optical network.

Abstract: An optical transmission system includes: multiplex transmitting devices, each configured to modulate, with an optical carrier, a data signal modulated into light by an optical modulator in a non-linear optical medium arranged on a transmission path so as to multiplex the data signal into the optical carrier, the data signal having a frequency different in each of the multiplex transmitting devices; a receiving device configured to execute optical-to-electrical conversion on the optical carrier received from the transmission path so as to execute reception process of the data signals multiplexed by the multiplex transmitting devices; and a management device configured to specify a frequency band to be used, based on a modulation band of each of the optical modulators, and manage assignment of the frequency of each of the data signals within the frequency band to be used so as to avoid an effect of harmonics generated upon the optical-to-electrical conversion.

Abstract: An optical packet switching system includes an optical packet transmitter, an optical packet switching apparatus, an optical amplifier, an optical packet receiver, an information gathering unit, and a peak power calculation unit. The information gathering unit collects the packet density, time-averaged power and extinction ratio from the optical packet transmitter, collects the packet density, time-averaged power and noise figure from the optical amplifier, collects the packet density, time-averaged power, switch on/off time ratio and extinction ratio from the optical packet switching apparatus, and collects the packet density and time-averaged power from the optical packet receiver. The peak power calculation unit calculates the peak power of an optical packet signal outputted from each apparatus/device based on the collected information.

Abstract: An adaptive coding scheme for nonlinear channels improves reliability and an efficiency in digital communication networks. The method monitors channel statistics to analyze an extrinsic information transfer chart of the channels. The channel statistics are fed back to the transmitter to adapt forward error correction coding. A parametric analysis method uses a Gaussian mixture model. The statistical information feedback can adapt an ARQ sheme by adding a weighted received signal to the original coded signals to reduce nonlinear distortion. Trellis shaping can make the transmitting signal preferable for nonlinear channels.

Abstract: The present invention discloses an adapting apparatus and method, the apparatus comprises: an adapter pool, wherein the adapter pool is located between an optical data unit (ODUk) layer and an optical channel (OCh) layer, and the adapter pool comprises one or more adapters which are respectively connected to an OCh layer link and an ODUK layer link; the information that the adapter pool used for managing comprises: information for indicating connectivity of the adapter with the OCh layer link and with the ODUk layer link, and information for indicating an adapter capability of the adapter. The adapting information between MRNs can be described more accurately through the present invention, and the correctness of the route calculation results is guaranteed.

Abstract: An optical hybrid (100) generates a first optical signal by causing local light to interfere with a received optical signal which is received from an outside with a first phase difference. In addition, the optical hybrid (100) generates a second optical signal by causing the local light to interfere with the received optical signal with a second phase difference shifted by ? from the first phase difference. Two photoelectric conversion elements (150) photoelectrically convert the first optical signal and the second optical signal, respectively, and generate a first electrical signal and a second electrical signal. A differential trans-impedance amplifier (200) includes a direct-current component correction unit (210), a trans-impedance circuit (240), and a variable gain amplifier (250).

Abstract: A method of registering a coax network unit (CNU) in a network is performed at an optical-coax unit (OCU). In the method, a first discovery message is broadcasted to a plurality of CNUs. In response, a first registration request is received from a first CNU of the plurality of CNUs. In response to the first registration request, a proxy entity corresponding to the first CNU is implemented in the OCU. A second discovery message is received from an optical line terminal (OLT). In response to the second discovery message, a second registration request is transmitted to the OLT requesting registration of the proxy entity with the OLT.

Abstract: A method for nonlinearity compensation for an optical transmission link includes determining a dispersion effect of a transmission link; applying a phase conjugation to the transmission link, the phase conjugation responsive to an input wave over the transmission link and providing a conjugated version of the input wave; and configuring an optimum equivalent link responsive to the phase conjugation after the transmission link to compensate for a non-linear dispersion effect from said transmission link.

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: An optical communication system provides coherent optical transmission for metro applications. Relative to conventional solutions, the optical communication system can be implemented with reduced cost and can operate with reduced power consumption, while maintaining high data rate performance (e.g., 100 G). Furthermore, a programmable transceiver enables compatibility with a range of different types of optical networks having varying performance and power tradeoffs. In one embodiment, the optical communication system uses 100 Gb/s dual-polarization 16-point quadrature amplitude modulation (DP-16QAM) with non-linear pre-compensation of Indium Phosphide (InP) optics for low power consumption.

Abstract: Component signal values are derived from component signals and fed to at least one fixed equalizer which generates equalizer output signals. The signals are fed to phase error detectors generating phase error signals. The phase error signals are combined with further phase error signals derived by further error detectors receiving signal values from further equalizers and/or the component signal values directly from sample units.