Abstract: An optical line terminal which includes an observing unit that observes information of any one or all of an arrival interval of frames, an instantaneous bandwidth under use of a flow, a queue length of a queue temporarily storing the frames, and a traffic type, and a stop determining unit that dynamically determines a sleep time to be a period in which a sleep state where partial functions of the ONU are stopped is maintained, on the basis of the information obtained by the observing unit. The ONU is entered into a sleep state, immediately after communication ends, after a predetermined waiting time passes from when the communication ends, or after a waiting time determined on the basis of the information passes from when the communication ends.

Abstract: A system includes a network having multiple network nodes each configured for free-space optical communication. Each network node includes one or more apertures through which optical beams are transmitted and received over optical links. The optical links include (i) a traffic link that transports higher-rate traffic between nodes and (ii) an acquisition/tracking link that transports lower-rate signals used to establish and maintain location knowledge of other nodes. Each network node also includes a network processor configured to determine one or more backup paths through the network. Each network node further includes a beam steering unit configured to redirect an optical beam from the traffic link onto the acquisition/tracking link to create a backup traffic link.

Abstract: There is provided a distance-adaptive and fragmentation-aware all-optical traffic grooming (DFG) method, which addresses the all-optical traffic grooming problem while considering the transmission reach constraints. The DFG procedure provisions traffic demands in optical channels such that the spectrum requires for guard bands is minimized. The DFG procedure provisions optical channels such that network fragmentation is minimized while ensuring the transmission reach constrains over flexible-grid WDM networks.

Abstract: Consistent with the present disclosure a transmitter is provided that transmits data in either a “quasi-DP-BPSK” (“QDP”) mode or in a DP-QPSK mode. In the QDP mode, data bits are transmitted as changes in phase between first and second phase states along a first axis or as changes in phase between third and fourth phase states along a second axis in the IQ plane. Although the transmitter outputs an optical signal that changes in phase between each of the four states, a sequence bit identifies which axis carries the data bit. The sequence bit is one of a series of sequence bits that may be generated by a pseudo-random number generator. The series of sequence bits can be relatively long, e.g., 32 bits, to permit sufficiently random changes in the axis that carries the data.

Abstract: A system and method for applying an extended multipoint control protocols to wireless access systems. A medium-to-medium adaptor can be provided in an adaptor node that can interface with an upstream optical line terminal in a PON domain and a downstream device in a non-PON wireless domain. The medium-to-medium adaptor enables an implementation of end-to-end services across multiple quality of service (QoS) domains by passing all traffic with controlled delay and without contention.

Abstract: An optical signal output apparatus includes: a switch having a first state or a second state in accordance with user's operation; and an optical signal output section that outputs a low-level optical signal when the switch is in the first state, whereas outputting a high-level optical signal when the switch is in the second state.

Abstract: An optical line terminal which includes an observing unit that observes information of any one or all of an arrival interval of frames, an instantaneous bandwidth under use of a flow, a queue length of a queue temporarily storing the frames, and a traffic type, and a stop determining unit that dynamically determines a sleep time to be a period in which a sleep state where partial functions of the ONU are stopped is maintained, on the basis of the information obtained by the observing unit. The ONU is entered into a sleep state, immediately after communication ends, after a predetermined waiting time passes from when the communication ends, or after a waiting time determined on the basis of the information passes from when the communication ends.

Abstract: A phase synchronized optical master-slave loop comprises at the slave-end a processor (105) configured to include a first timing signal into a bit stream to be transmitted to the master-end, detect a second timing signal from a bit stream received from the master-end, and calculate a phase difference between a regenerated phase signal and a reference phase signal on the basis of a transmission moment of the first timing signal, a first time-stamp indicating a reception moment of the first timing signal at the master-end, a reception moment of the second timing signal, and a second time-stamp indicating a transmission moment of the second timing signal from the master-end. The processor is configured to read the time stamps from the received bit stream that corresponds to a received light signal according to a reception line-code. Thus, conversion of data format is not necessary for the phase synchronization.

Abstract: We disclose an optical receiver having a configurable clock-recovery module, an operative configuration of which is selectable based on a bandwidth of the optical input signal. In an example embodiment, the clock-recovery module adopts a first configuration for non-Nyquist optical input signals, and adopts a different second configuration for Nyquist and faster-than-Nyquist optical input signals. The configurability of the clock-recovery module may advantageously prevent the clock-recovery algorithm from breaking down, e.g., due to variability of the bandwidth of the optical input signal caused by the variability of the routes that optical signals may take in the corresponding optical-transport network before arriving at the optical receiver.

Abstract: An optical network node includes first and second node inputs receiving first and second multiplexed optical signals, respectively. The optical network node includes node outputs, each outputting a separate replicated or demultiplexed optical signal. The optical network node includes a first optical power splitter having a first splitter input connected to the first node input and first splitter outputs connected to the node outputs. The optical network node includes a second optical power splitter having a second splitter input connected to the second node input and second splitter outputs connected to the node outputs. The optical network node includes an arrayed waveguide grating having a grating input connected to the first node input and grating outputs connected to the node outputs, the arrayed waveguide grating demultiplexing the first multiplexed optical signal, when the first multiplexed optical signal is wavelength division multiplexed.

Abstract: A method of operation of an optical network communication system including: providing a planar lightwave circuit including: connecting 2×2 single-mode optical couplers in an array for forming a 1×N single-mode optical splitter/combiner, and routing harvesting ports to an optical line terminal receiver for collecting harvested-light, from two or more of the harvesting ports, in the optical line terminal receiver wherein one of more of the harvesting ports is from the 2×2 single-mode optical couplers; transmitting to an optical network unit through the planar lightwave circuit at a first wavelength; and interpreting a response from the optical network unit at a second wavelength through the harvested-light.

Abstract: Method and system for optimally equalizing distortion of an optical data channel carrying coherent optical signals with a given analog bandwidth B. A receiving end with IQ paths receives signals and a balanced detector detects signals in each path. The bandwidth of the detected signals is reduced by a factor of N by filtering the output of each path using an AAF with a cutoff frequency optimized to the analog bandwidth 2B/N of each path, where the AAF has deterministic attributes and introducing Known ISI. The signal is sampled at the AAF output by an ADC, at a sampling rate of 2B/N. The samples of each path are post-processed by a digital processor operating at a data rate of 2B/N, where post-processing represents the compensation of the distortion and the input data stream is reconstructed by optimally decoding the output of the processor using a decoder, which compensates the ISI.

Abstract: An integrated system of infrared remote controls includes a touch remote control and at least one infrared emitter. The touch remote control is wirelessly connected with the infrared emitter to transmit a remote signal. Each infrared emitter is mounted on a home appliance. When the infrared emitter receives the remote signal, the infrared emitter produces an infrared signal according to the remote signal and emits the infrared signal to the home appliance to control the home appliance. The infrared emitter can be adhered to or attracted on the home appliance by an adhesive layer or a magnet. Therefore, the infrared emitter can be easily mounted on the home appliance. It is very convenient for a user to set up and use the integrated system.

Abstract: Disclosed is a spatial switching apparatus having a plurality of input terminals, an input optical signal of a single wavelength being input to each of the plurality of the input terminals, and a plurality of output terminals an output optical signal of a single wavelength being output from each of the plurality of the output terminals. The apparatus includes a signal wavelength converting portion having an electric signal converting element converting the input optical signal into an electric signal and a variable wavelength laser, the signal wavelength converting portion using the variable wavelength laser to convert an electric signal converted by the electric signal converting element into an optical signal of an arbitrary wavelength; and a spatial switching portion having a plurality of first cyclic AWGs performing output from a plurality of output ports corresponding to wavelengths of a plurality of input signals input from the variable wavelength laser.

Abstract: An example embodiment includes an optical transmission device. The optical transmission device includes an optical source, a collimator lens, and an optical monitor. The optical source is configured to transmit a channel of light. The collimator lens is configured to reflect a portion of the channel of light. The optical monitor is arranged to receive at least a first portion of the reflected channel of light directly from the collimator lens, and is configured to communicate a gross electrical signal representative of received light including the first portion of the reflected channel of light.

Abstract: An optical communication system includes a transmission apparatus that transmits a test signal over an optical communication medium using a first optical modulation format, receives a reception report for the test signal, determines, based on the received reception report, a pre-equalization scheme, applies the pre-equalization to data transmitted from the transmitter side to generate pre-equalized data and transmits the pre-equalized data using a second optical modulation format based on the reception report. An optical reception apparatus receives the test signal, computes a channel transfer function based on the received test signal, and transmits the reception report.

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 receiver for an optical communications system which corrects distortion of a received signal. A clock recovery system utilizing a feedback and feedforward system are provided. The feedback loop comprises a phase detector and a clock source, while the feedforward loop comprises the phase detector and a delay element for delaying the output of distortion correction system. The feedback loop has a significantly lower bandwidth than the feedforward path. There are also provided methods of optimizing tap weights and of acquiring initial tap weights.

Abstract: Method and arrangement for protecting optical network systems, the arrangement (20) is based on an optical electrical optical GPON repeater structure. The repeater structure contains two optical modules—a regular ONU transceiver module and a reset-less OLT transceiver module which are working back-to-back. For management purposes, an ONU MAC module comprised in the repeater structure is intercepting the electrical signals from the ONU transceiver. The arrangement comprising the two repeater structures can be used to relay data between two passive optical network (PON) systems thereby opening a way to implement dual homing via the PON domain. Moreover, the arrangement is configured to enabling switch-over of functionality from one PON to the other PON at a communication failure in the former PON.

Abstract: The invention relates to a method for synchronizing RF antenna signals (5a to 5i) of a plurality of RF antenna sites (3a to 3i) arranged at different locations of a radio transmission system (1b), the method comprising; generating a reference signal (7) in a reference oscillator (6) located at a central unit (2) of the radio transmission system (1b), transmitting the reference signal (7) as an optical signal from the central unit (2) to the RF antenna sites (3a to 3i) via a plurality of optical fiber links (9a? to 9i?), and using the transmitted reference signal (7) for synchronizing the RF antenna signals (5a to 5i) of the different RF antenna sites (3a to 3i), The invention also relates to a radio transmission system (1b).