Abstract: A routing and wavelength assignment method for use in an optical fiber system, comprising: (i) identifying a plurality of paths between a source node and a destination node, (ii) selecting one of the plurality of identified paths, (iii) defining within the spectrum band of the selected path one or more blocks of spectral resource, in which each block comprises either: one or more unused wavelength channels, or one or more wavelength channels having the same spectral width, (iv) obtaining an entropy value of the selected path defining the spectrum fragmentation across its spectrum band, based on a logarithm of the ratio of the number of wavelength channels in each of the one or more blocks, to the total number of wavelength channels across the spectrum band, (v) iterating (ii) to (v) until the entropy value of each of the plurality of identified paths has been determined, and (vi) choosing from the plurality of identified paths a path having the lowest entropy value.

Abstract: A dual wavelength Optical Time Domain Reflectometer (OTDR) system, embedded in a network element, includes a first OTDR source for wavelength ?1; a second OTDR source for wavelength ?2; an OTDR measurement subsystem adapted to measure backscatter signals ?1_BACK, ?2_BACK associated with the wavelength ?1 and the wavelength ?2; and one or more ports connecting the first OTDR source, the second OTDR source, and the OTDR measurement subsystem to one or more fiber pairs; wherein wavelength ?1 and wavelength ?2 are each outside of one or more signal bands with traffic-bearing channels, thereby enabling operation in-service with the traffic-bearing channels.

Abstract: A multifunctional laser driving circuit, and an optical module and method of using the same, are disclosed. The circuit combines first and second optical signals having different functions to form a compound signal, and switches among the first optical signal, second optical signal and compound signal by enabling or disabling first and second laser drivers corresponding to the first and second optical signals. The circuit can provide functions to optical modules, including converting an electrical data signal into an optical data signal; converting an electrical line monitoring signal into an optical line monitoring signal; combining the optical data and line monitoring signals and synchronously transmitting them to a fiber; and providing an OTDR function. Relative to using external OTDR tools to detect line faults, the present circuit and method enables simple line connection, timely detection of lines faults, and low costs of implementation.

Abstract: Techniques are described for determining pre-compensation parameters to compensate for signal integrity degradation along a signal path. A processor generates a first digital signal and receives a second digital signal. The second digital signal is generated from an optical-to-electrical conversion of a feedback optical signal that is generated from an electrical-to-optical conversion of an electrical signal by an optical module. The processor determines the pre-compensation parameters based on the first and second digital signals.

Abstract: An apparatus and method for providing a differential latency, DL, between an upstream, US, transmission and a downstream, DS, transmission via an optical transmission link (OTL), said apparatus comprising a measurement unit (2) configured to measure the round trip delays, RTD, of at least two measurement signals having different measurement wavelengths; and a processing unit (3) configured to derive an upstream, US, delay of at least one optical signal at an upstream wavelength from the at least two measured round trip delays, RTD, and to derive a downstream, DS, delay of at least one optical signal at a downstream wavelength from the at least two measured round trip delays, RTD, wherein the differential latency, DL, is calculated on the basis of the derived delays, RTD.

Abstract: A system and method for automatically steering an optical data signal from a transceiver of a base station to a selected mobile endpoint of a plurality of mobile endpoints in a virtual reality or an augmented reality space may include a tracking device that communicates with the base station to establish and track a current location of the selected mobile endpoint. A steering mechanism may steer an optical beam to the determined current location of the selected mobile endpoint and transmit the optical beam to the determined current location of the selected mobile endpoint to transmit an optical data signal to the selected mobile endpoint.

Abstract: A bi-directional optical transceiver module includes: an optical transmission unit to output a transmission signal; an optical reception unit to receive a reception signal, the transmission signal and the reception signal having different corresponding first and second wavelength values within a single channel; a splitter, inclined with respect to an incident direction of the transmission signal output from the optical transmission unit, to transmit the transmission signal to an outside, and reflect optical signals input from the outside, the optical signals including the reception signal; and a reflected light-blocking optical filter unit to pass, as the reception signal among the optical signals reflected by the splitter, an optical signal within a preset wavelength range including the second wavelength value.

Abstract: Methods and systems for hybrid integration of optical communication systems are disclosed and may include receiving continuous wave (CW) optical signals in a silicon photonics die (SPD) from an optical source external to the SPD. The received CW optical signals may be processed based on electrical signals received from an electronics die bonded to the SPD via metal interconnects. Modulated optical signals may be received in the SPD from optical fibers coupled to the SPD. Electrical signals may be generated in the SPD based on the received modulated optical signals and communicated to the electronics die via the metal interconnects. The CW optical signals may be received from an optical source assembly coupled to the SPD and/or from one or more optical fibers coupled to the SPD. The received CW optical signals may be processed utilizing one or more optical modulators, which may comprise Mach-Zehnder interferometer modulators.

Abstract: The present invention provides systems, methods, and apparatuses for subsea optical to electrical distribution. The present invention comprises one or more routing units adapted to convert optical signals to electrical signals and route the converted electrical signals to an appropriate end device. The routing unit is a compact device that may be installed without the use of heavy equipment.

Abstract: A current mirror circuit that amplifies a reference current generated by a current source at a first magnification to supply a mirror current to a load circuit. The current mirror circuit includes a first transistor and a second transistor that share a power supply, and a drain potential mirror unit that amplifies the reference current at a second magnification to generate a first current, that amplifies a generated first current at a third magnification to generate a second current, and that supplies a predetermined potential determined based on the second current to a drain of the second transistor. The mirror current is supplied from the second transistor to the load circuit based on a potential of a gate of the first transistor determined based on the reference current.

Abstract: A nonlinear compensation unit (300) includes a first compensation unit (350) and a second compensation unit (360). The first compensation unit (350) compensates for each of two polarization signals Ex and Ey so as to cancel a first amount of phase rotation which is the amount of phase rotation calculated based on the signal strength of the two polarization signals Ex and Ey. The second compensation unit (360) compensates for each of the two polarization signals Ex and Ey so as to cancel a second amount of phase rotation which is the amount of phase rotation calculated based on the perturbative component of the two polarization signals Ex and Ey. The first compensation unit (350) includes a strength calculation unit (302), a first filter unit (304), and a first phase modulation unit (306). The second compensation unit (360) includes a perturbative component calculation unit (316), a second filter unit (318), a second phase modulation unit (322), and a third phase modulation unit (330).

Abstract: A temperature insensitive DEMUX/MUX device whose wavelength does not change by environment temperature is provided for WDM application. The temperature insensitive DEMUX/MUX device includes a waveguide-based delay-line-interferometer configured to receive an input light bearing multiplexed wavelengths and output a first output light bearing the same multiplexed wavelengths but with a shifted intensity peak position. The first output light is transmitted into a DEMUX device through a first free space coupler and a grating fiber or waveguide to be demultiplexed for forming a plurality of second output lights each bearing an individual wavelength. The DEMUX device includes a second free space coupler for refocusing each second output light to corresponding output channel. The shifted intensity peak position of the first output light is tunable to make each second output light free from any temperature-induced drift off corresponding output channel.

Abstract: An opto-electrical oscillator includes, in part, first and second optical phase modulators, a coupler, an optical-to-electrical signal conversion circuit, and a control circuit. The first optical phase modulator modulates the phase of a first optical signal in response to a first feedback signal to generate a first phase modulated signal. The second optical phase modulator modulates the phase of a second optical signal in response to a second feedback signal to generate a second phase modulated signal. The first and second optical signals travel through first and second optical paths respectively and are generated from the same optical source. The optical-to-electrical signal conversion circuit receives an optical signal from the coupler and in response generates an electrical signal applied to the control circuit. The output signals of the control circuit cause the first and second feedback signals to be out of phase.

Abstract: A probe generator includes: a first demultiplexer configured to branch a first optical signal having a first wavelength into at least two first polarized optical signals; a first adjustor configured to adjust the first polarized optical signals such that the first polarized optical signals have the same polarization direction and to combine the adjusted first polarized optical signals into a second optical signal; a first modulator configured to branch the second optical signal into at least two first split optical signals and to intensity-modulate each of the first split optical signals with first pilot signals; a second adjustor configured to adjust the first split optical signals intensity-modulated by the first modulator such that the intensity-modulated first split optical signals have different polarization directions; and an output unit configured to combine the first split optical signals adjusted by the second adjustor to generate a probe optical signal to be output.

Abstract: Provided are methods, apparatuses and a system for monitoring a Reconfigurable Optical Add Drop Multiplexer (ROADM) optical network. The method includes: loading, in an optical signal at a sending end, a wavelength label frequency and attribute information of a channel used for transmitting the optical signal; sending the wavelength label frequency and/or the attribute information; receiving, at a monitoring end, the optical signal and acquiring, from the optical signal, the wavelength label frequency and/or the attribute information of the channel used for transmitting the optical signal; and monitoring the ROADM optical network according to the wavelength label frequency and/or the attribute information. The technical solution solves the technical problem in related art that the ROADM optical network cannot be effectively monitored, and achieves the effective monitoring of the ROADM optical network.

Abstract: An optical receiver is described. Using silicon-photonic components that support a single polarization, the output of an optical receiver is independent of the polarization of an optical signal. In particular, using a polarization-diversity technique, the two orthogonal polarizations in a single-mode optical fiber are split in two and processed independently. For example, the two optical signals may be provided by a polarization-splitting grating coupler. Subsequently, a redistribution element provides mixtures of the two optical signals. Next, a wavelength channel in the two mixed optical signals is selected using a wavelength-selective filter (for example, using ring-resonator drop filters or an echelle grating) and converted into an electrical signal at an optical detector (such as a photodetector) to achieve polarization-independent operation.

Abstract: A control system includes a plurality of subscriber devices of a communications network, these subscriber devices communicating with one another by optical signals. A subscriber device includes two opposing faces, an optical shutter controllable between an at least partially transparent state and an opaque state, the optical shutter traversing a part of the subscriber device between the two opposing faces; a control circuit configured for controlling the controllable optical shutter; an optical signal emitter on a first of the two opposing faces, disposed in such a manner as to allow the emission of optical signals toward a first neighboring subscriber device; and an optical signal receiver on a second of the two opposing faces, disposed in such a manner as to allow optical signals to be received that originate from a second neighboring subscriber device.

Abstract: A distributed antenna system is provided for communicating with a plurality of base stations. The distributed antenna system includes a system controller and a master unit communicating with at least one of the plurality of base stations. A remote unit communicates over a high data rate media with the master unit and/or a downstream remote unit. Alternatively, the distributed antenna system includes a controller and a digital time/space crosspoint switch controlled by the controller. A digitizing transceiver is in communication with the digital time/space crosspoint switch. The crosspoint switch is configured to transmit and receive digital data through the digitizing transceiver.

Abstract: An optical communication device and a control method thereof are provided. The optical communication device includes a driving module, a data transmission module, a light emitting module, and a feedback module. The driving module generates a driving current. The data transmission module generates a data current according to a piece of data. The light emitting module is electrically connected to the driving module and the data transmission module directly and emits visible light according to an illuminating current generated by combining the driving current with the data current. The feedback module adjusts a direct current (DC) potential of one of the driving current and the data current so as to make an average intensity of the visible light equal a preset intensity.

Abstract: The present invention can operate a reflective semiconductor optical amplifier at ultrahigh speed using a polar return-to-zero (RZ) modulation method, and operate a reflective semiconductor optical amplifier (RSOA) whose modulation bandwidth is limited at ultrahigh speed by generating signals vertically symmetrical using a newly suggested polar RZ signal generator when generating an amplitude modulation signal at a transmission end. The present invention can overcome the problem that a modulation speed cannot be increased to 10 Gb/s or above due to signal distortion by inter-symbol-interference when generating an ultrahigh speed amplitude modulation signal using an RSOA of low price having a very narrow modulation bandwidth in an RSOA-based optical network.