Abstract: A method and a Reconfigurable Optical Add Drop Multiplexer (ROADM) where blocking of a first optical signal carried over a specific optical channel in the ROADM is performed by compensating the first optical signal by a second optical signal created for that purpose.

Abstract: Embodiments of the present invention relate to a bi-direction optical sub-assembly and an optical transceiver. A transmitter in the bi-direction optical sub-assembly is configured to transmit a first communication signal or a detection signal, where the first communication signal or the detection signal is input from a first end of a first optical path and output from a second end of the first optical path, enters a second end of a third optical path through reflection of a WDM optical filter, and is input from a first end of the third optical path to an optical fiber. A second communication signal received by the optical fiber is input from the first end of the third optical path and output from the second end of the third optical path, and the second signal is received by a BOSA receiver through transmission of the WDM optical filter.

Abstract: A reflective optical network (10) comprises an optical network unit (14) and an optical receiver (22). The optical network unit (14) comprises a reflective optical modulator (16) arranged to receive a seed optical signal, and a transmitter controller (18) arranged to receive a data signal (20) and to control the modulator (16) to apply the data signal (20) to the seed optical signal, to form an optical data signal. The transmitter controller (18) is arranged to process the data signal (20) to substantially prevent the optical data signal comprising spectral components at frequencies lower than a cut-off frequency, being the frequency at which a power spectral density of said optical data signal is lower than a peak power spectral density of said optical signal by a cut-off power value. The optical receiver (22) comprises an electrical domain high pass filter (26) having a cut-off frequency higher than a linewidth of the seed optical signal.

Abstract: There is provided a method in a wavelength convertible flexible optical wavelength-division multiplexing (WC-FWDM) network. The network has a plurality of optical nodes interconnected by a plurality of optical fibers. The network is for providing an overall spectrum divisible into a set of consecutive wavelength slots. At least one optical node has at least one wavelength converter for wavelength conversion. The method includes determining a channel route through the network commencing at a source node and ceasing at a destination node. The determined channel route is selectively tunable responsive to selected ones of a plurality of routing methods. The routing methods are so selected responsive to a routing policy having one or more objectives of minimization of channel blocking, minimization of a number of wavelength converters used in the network, and minimization of physical distance traversed by a channel, and minimization of operating wavelengths of a channel.

Abstract: A method for regenerating optical signal includes determining a source optical signal to be regenerated, adding a first pump optical signal and a second pump optical signal to the source optical signal to yield an intermediate optical signal, creating a first conjugate optical signal and a second conjugate optical signal from the intermediate optical signal, and performing degenerate phase-sensitive amplification utilizing the first conjugate optical signal, the second conjugate optical signal and the source optical signal to yield an output optical signal. The source optical signal is modulated with a multilevel modulation format. Each conjugate optical signal has a phase that is a conjugate of a multiple of the phase of the source optical signal.

Abstract: A method of generating an optical radiation signal is to be implemented by an optical radiation signal generating device including a dual beam generating unit for receiving an original optical input signal, and a second-order fiber Bragg grating (FBG). The dual-beam generating unit is configured to generate, from the original optical input signal, first and second optical input signals having a phase difference therebetween. The second-order FBG is configured to receive the first and second optical input signals, and to radiate an optical radiation signal by interference between the first and second optical input signals.

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 polarization-multiplexed signal receiver includes a polarization adjustment unit to adjust a polarization state of inputted polarization-multiplexed signal, which is carrying signal data on each of two polarized waves being inputted, based on a control signal and to output the adjusted polarization-multiplexed signal, an optical signal reception unit to convert the polarization-multiplexed signal having the adjusted polarization state into an analog electric signal and output the analog electric signal, an A/D conversion unit to convert the analog electric signal into a digital electric signal and output the digital electric signal, a digital signal processing unit to perform digital coherent processing to the digital electric signal and take out the signal data and a feedback control unit to generate the control signal based on quality of the signal data and output the signal data to the polarization adjustment unit.

Abstract: An optical packet switching apparatus includes an optical packet switching apparatus, an optical transmitting apparatus, and an optical packet receiving apparatus. The optical packet transmitting apparatus includes a packet generator for generating a packet signal by adding the routing information to a received client signal, a BIP adding unit for adding BIP to the generated packet signal, and an electrical-to-optical converter for converting the packet signal, to which the BIP has been added, into an optical packet signal so as to be sent out. The optical packet receiving apparatus includes an electrical-to-optical converter for converting the received optical packet signal into an electrical packet signal, and a BIP comparison unit for detecting the error occurrence in the packet signal, based on the BIP added to the packet signal.

Abstract: A method of providing routes through heterogeneous subsystems in an optical network is disclosed, which includes generating, using a processing device, a reachability matrix based on subnetwork information; and generating, using the processing device, a topology associated with the optical network using the reachability matrix. The method also includes determining, using the processing device, a shortest path through the optical network using the reachability matrix and a cost model graph; and displaying, using a graphical user interface, subsystems associated with the shortest path, regeneration locations associated with the shortest path, wavelengths associated with the shortest path, the topology, and the shortest path. Corresponding apparatus and computer-readable storage media are also disclosed.

Abstract: A sending/receiving system includes first and second sending/receiving apparatuses. The first sending/receiving apparatus includes a first sending section that sends link establishment information via first transmission channels. The second sending/receiving apparatus includes a second sending section, link establishing sections, and a controller. The second sending section sends link establishment information to the first sending/receiving apparatus via a second transmission channel. Each of the link establishing sections is provided for a corresponding one of the first transmission channels and establishes a link in the corresponding first transmission channel on the basis of the link establishment information.

Abstract: To stabilize power to an optical multimode receiver a multimode variable optical attenuator is connected to the receiver with the attenuator's voltage being controlled using a feedback signal provided by an output detector, the signal being processed using a control algorithm based on proportional-integrate-differential theory.

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 optical networks new links are added between nodes over time to satisfy the increasing traffic demands of the network. Existing links are normally not changed, resulting in a network that does not have the lowest energy consumption. A method provides a way to reduce the energy consumption of the overall network while supporting the required traffic demands at all times. The network includes a multiple source nodes, and multiple destination nodes. The network is represented by a graph of nodes connected by edges, wherein each node represents an optical network element and each edge represents a path connecting two optical network elements. Each edge is labeled with a demand. The non-bridge edge with a lowest demand is removed from the graph, and the lowest demand is added to the non-bridge edge with a highest demand. These steps are repeated until a termination condition is reached.

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: At least one segment is identified in an audio signal. The audio segment is associated with an artifact within the audio signal and has a time duration. At least one stored sound clip is retrieved, which has a time duration that exceeds the time duration associated with the audio segment. The retrieved sound clip is mixed with the audio signal and the retrieved sound clip audibly compensates for the audio artifact.

Abstract: Carrier phase estimation techniques are provided for processing a received optical signal having a carrier modulated according to a modulation scheme. First and second carrier phase estimation operations are performed on a digital signal derived from an optical carrier obtained from the received optical signal using coherent optical reception. The first carrier phase estimation operation tracks relatively fast phase variations of the optical carrier of the received optical signal to produce a first carrier phase estimation and the second carrier phase estimation operation tracks relatively slow phase variations of the optical carrier of the received optical signal to produce a second carrier phase estimation. A difference between the first and second carrier phase estimations is computed. Occurrence of a cycle slip is determined when the difference is greater than a threshold. A correction is applied to the first carrier phase estimation when the low pass filtered difference exceeds the threshold.

Abstract: An LED light and communication system is in communication with a broadband over power line communications system. The LED light and communication system includes at least one optical transceiver. The optical transceiver includes a light support having a plurality of light emitting diodes and at least one photodetector attached thereto, and a processor. The processor is in communication with the light emitting diodes and the at least one photodetector. The processor is constructed and arranged to generate a communication signal.

Abstract: An optical packet switching device is provided with: a first input unit and a second input unit for receiving optical packet signals having destination information and information of a wavelength in use; an optical switch unit for routing the optical packet signals; a branching unit for branching the received optical packet signals; an analyzer unit for analyzing the header of the branched optical packet signals so as to detect the destination information and the information of the wavelength in use; and an output competition determination unit for checking for temporal competition of the optical packet signals based on the destination information and for determining whether the optical packet signals should be transmitted or discarded based on the information of the wavelength in use when there is competition.

Abstract: An example is a bandwidth control method employed in an optical line terminal including: determining a first time point at which a first optical network unit starts the processing of transitioning between the states in a case where the first optical network unit is to be transitioned between the states; transmitting a state control signal containing the first time point to the first optical network unit in order to control the first optical network unit to start the processing of transitioning between the states; and stopping allocating a bandwidth used to transmit a signal to the optical line terminal to a second optical network unit during a period from the first time point until it is determined that the first optical network unit has finished the processing of transitioning between the states.