Abstract: In an optical fiber network for transmitting optical signals in a robot having three or more joints connecting a plurality of links in series such that the links include two end links located at either end and intermediate links provided between the two end links, and the links connected by the joints are moveable relative to each other, a plurality of optical transceiver modules are provided on the links such that at least one optical transceiver module is provided on each link; and a plurality of optical fiber cables connect the optical transceiver modules in a ring; wherein at least one end of each optical fiber cable connecting the optical transceiver modules provided on different links is connected to one of the optical transceiver modules provided on the intermediate links.

Abstract: An apparatus comprises a polarization-diversity optical hybrid that converts an optical signal into a plurality of optical signals comprising a first polarization component and a second polarization component orthogonal to the first polarization component, one or more detectors that convert the plurality of optical signals into a plurality of first analog electrical signals, DC blocking elements that remove DC signal components to output a plurality of second analog electrical signals, analog to digital converters (ADCs) coupled to the DC blocking elements that convert the plurality of second analog electrical signals into a plurality of digital signals, and a digital signal processing (DSP) unit coupled to the ADCs. The DSP is configured to perform a fiber dispersion compensation on the plurality of digital signals and add DC offsets to output a plurality of DC-restored compensated digital signals.

Abstract: An information transmission system includes a transmission apparatus and a reception apparatus and uses visible lights as transmission media. The transmission apparatus includes a generating unit and a first replace unit. The generating unit generates a multi-value symbol stream. The first replace unit replaces the multi-value symbol stream generated by the generating unit to a discontinuous symbol stream. The discontinuous symbol stream is a symbol stream without a sequence of identical symbol values. The number of identical symbol values in the sequence is equal to or greater than a predetermined number. The reception apparatus includes an acquiring unit and a second replace unit. The acquiring unit acquires the discontinuous symbol stream. The second replace unit replaces the discontinuous symbol stream acquired by the acquiring unit to the multi-value symbol stream according to a predetermined rule.

Abstract: A network capable of being used in a datacenter is described. The network can comprise a set of optical fiber rings, wherein each optical fiber ring carries data traffic on multiple wavelengths, and wherein each optical fiber ring is partitioned into multiple sectors. In some embodiments, each sector in the multiple sectors can comprise: (1) only one add-wavelength-selective-switch (add-WSS) communicatively coupled to only one optical fiber ring in the set of optical fiber rings, wherein the only one add-WSS is used for sending all data traffic that originates from the sector and is destined to other sectors; (2) an add-electro-optical-switch (add-EOS) communicatively coupled to the add-WSS; (3) a set of drop-wavelength-selective-switches (drop-WSSs) communicatively coupled to the set of optical fiber rings, wherein the set of drop-WSSs are used for receiving data traffic from other sectors; and (4) a drop-electro-optical-switch (drop-EOS) communicatively coupled to a drop-WSS in the set of drop-WSSs.

Abstract: A wavelength-selective device includes: a storage in which a wavelength management table is stored; and a processor configured to execute a procedure, the procedure including: searching for one or more paths used as a new path having a first ending time in a network, based on the wavelength management table; selecting a wavelength having a second ending time closest to the first ending time, from one or more wavelengths used on paths found by the searching; and configuring a path using the selected wavelength as the new path.

Abstract: An OLT (1) is formed by N optical transceivers (11), one PON control circuit (12), and one selection and distribution circuit (13). An optical transceiver selection control signal (SC) is transferred from the PON control circuit (12) to the selection and distribution circuit (13). The optical transceiver selection control signal (SC) indicates the timing of a discovery window, the timing of a grant, and a logical link identification number of a registered ONU assigned to the grant (a logical link identification number for a logical link with the registered ONU). The selection and distribution circuit (13) selects one optical transceiver (11-s (s is an integer falling within a range of 0 to N?1)) from the optical transceivers (11-0 to 11-N?1) based on the optical transceiver selection control signal (SC) from the PON control circuit (12).

Abstract: One embodiment provides an apparatus for coupling between a trunk passive optical network (PON) and a leaf PON. The apparatus includes a trunk-side optical transceiver coupled to the trunk PON, a leaf-side optical transceiver coupled to the leaf PON, and an integrated circuit chip that includes an optical network unit (ONU) media access control (MAC) module, an optical line terminal (OLT) MAC module, and an on-chip memory.

Abstract: Particular embodiments provide a method for delivering data in the upstream direction without the need for upstream radio frequency (RF) modulation. For example, in some embodiments, an optical network may reach to a gateway associated with a user device. The gateway may receive digital baseband data from the user device in the upstream direction. The gateway can then send the digital baseband data through the optical network without modulating the digital baseband signal via radio frequency. At the headend, because no modulation is performed in the upstream direction, there is no need for de-modulation in the headend. In one embodiment, a scheduler-based approach is used to avoid instances of optical beat interference in the upstream direction as only one upstream device that may interfere with other devices may be able to send data at one time.

Abstract: Disclosed is an optical coupler device, especially for monitoring purposes in an optical point-to-point transmission link, which includes a first, a second and a third optical port and is configured to transmit a first optical signal received at the first optical port to the second optical port and to transmit a second optical signal received at the second optical port to the first and third optical port according to a monitoring split ratio with respect to the optical power of the second optical signal, the first and second optical signal having a wavelength lying in a first optical band. The device is further configured to transmit a third and a fourth optical signal received at the third and the second optical port to the respective other optical port, the third and fourth optical signal having a wavelength lying in a second optical band. The device is controllable with respect to the monitoring split ratio and includes a control means adapted to receive a control signal.

Abstract: The present invention provides an optical module and an optical network system. A first chip is arranged on a lower cover plate, an upper cladding, which is close to a first PD, of the first chip is covered by a first upper cover plate; a first dividing groove divides the first chip into two parts, and a WDM and a light blocking material are arranged inside the first dividing groove, so as to block stray light transmitted inside the upper cladding, a sandwich layer, a lower cladding, and a base of the first chip; and a light blocking material is arranged on a side of the first upper cover plate facing the first LD, so as to block stray light transmitted on a surface of the first chip, thereby blocking the stray light that enters the first PD, and significantly reducing crosstalk of the optical module.

Abstract: A method and system for implementing visible light communication, a sending apparatus and a receiving apparatus are disclosed. The method includes: after performing constellation modulation on data to be sent, a sending end mapping a modulated signal to a corresponding luminescent light source and transmitting the data to be sent through an optical signal; a receiving end converting a received optical signal into an electrical signal, and determining a constellation modulation signal according to a luminescent light source corresponding to the received signal, and demodulating the constellation modulation signal to obtain received data.

Abstract: A transmission characteristics monitoring device monitors transmission characteristics of an optical transmission path between nodes. The device detects an average power of the frequency modulated optical signal and a slope of the transmission characteristics; generates a slope function that represents a slope of the transmission characteristics between first and second frequencies; generates a corrected power value by adding an integral of the slope function to a first power measurement value detected at the first frequency; calculates the transmission characteristics at the second frequency based on a second power measurement value detected at the second frequency when the difference between the second power measurement value and the corrected power value is smaller than a specified threshold; and calculates the transmission characteristics at the second frequency based on the corrected power value when the difference is greater than the specified threshold.

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.

Abstract: Novel tools and techniques that can be used to detect network impairment, including but not limited to impairment of optical fiber networks. In an aspect, such tools and techniques can be deployed at relatively low cost, allowing pervasive deployment throughout a network. In another aspect, such tools and techniques can take advantage of a “dying gasp,” in which a network element detects a sudden drop in received optical (or electrical) power, resolution, etc. at short time scales and sends a notification across the network before the connection is completely compromised. In yet another aspect, some tools can include a supervisory function to analyze aspects of the dying gasp with the goal to determine network segments associated with an impairment and an estimate of the location of an impairment within the network.

Abstract: A communications device may include a remote device having a first E/O modulator to modulate an optical carrier signal with an input signal having a first frequency, an optical waveguide coupled to the remote device, and a local device coupled to the optical waveguide. The local device may include an optical source to generate the optical carrier signal, a second E/O modulator to modulate the optical carrier signal with a reference signal to generate a modulated reference signal, an OIL source coupled to the second E/O modulator and to amplify the modulated reference signal, and an O/E converter coupled to the OIL source and to generate an output signal including a replica of the input signal at a second frequency based upon the reference signal.

Abstract: A method and an apparatus for self-calibration of an ONU receiver in a multi-wavelength PON system, said method including the initial physical layer scan of the receiver tuning range, distributed estimation of the down-stream wavelength channel drift with respect to the nominal standard-based wavelengths, and reporting the estimated downstream wavelength channel drift in the downstream Channel_Map message.

Abstract: An apparatus comprising a digital signal processor (DSP) unit configured to perform fiber dispersion pre-compensation on a digital signal sequence based on a dispersion value to produce a pre-compensated signal, wherein the dispersion value is associated with a remote optical receiver, a plurality of digital-to-analog converters (DACs) coupled to the DSP unit and configured to convert the pre-compensated signal into analog electrical signals, and a frontend coupled to the DACs and configured to convert the analog electrical signals into a first optical signal, adding a constant optical electric (E)-field to the first optical signal to produce a second optical signal, and transmit the second optical signal to the remote optical receiver.

Abstract: An optical transceiver comprises a transmitter configured to transmit a first signal, and a receiver coupled to the transmitter and configured to receive a first compensation, wherein the first compensation is based on a pattern-dependent analysis of the first signal, and provide the first compensation to the transmitter, wherein the transmitter is further configured to compensate a second signal based on the first compensation to form a first compensated signal, and transmit the first compensated signal. An optical transmitter comprises a digital signal processor (DSP) comprising a compensator, a digital-to-analog converter (DAC) coupled to the DSP, a radio frequency amplifier (RFA) coupled to the DAC, and an electrical-to-optical converter (EOC) coupled to the RFA. An optical receiver comprises an optical-to-electrical converter (OEC), an analog-to-digital converter (ADC) coupled to the OEC, and a digital signal processor (DSP) coupled to the ADC and comprising a calibrator.

Abstract: An optical path for transmission of data from a source node to a destination node comprises an optical channel for parallel transmission of non overlapping carrier frequencies. The frequency separation of the carriers is lower than the baud rate. The optical path is configured by (a) determining a path OSNR (OSNRp ); (b) selecting a carrier bandwidth (BW) so that the channel bandwidth (BWT ) is less than or equal to a maximum path bandwidth available for transmission, wherein BWT?BW·C, wherein C is the number of carrier frequencies; (c) selecting a FEC code having a minimum overhead requirement; (d) determining a channel OSNR (OSNRT ) based on the currently selected BW and FEC code; (e) in response to determining that OSNRT is not less than or equal to OSNRp, reselecting new codes having increasing overhead requirements until OSNRT is less than OSNRp, and if this is not possible increasing BWT and returning to step (c); (h) configuring the path for transmission based on the finally selected BWTand FEC code.

Abstract: An apparatus comprising a frontend configured to convert an optical IM signal associated with a remote optical transmitter into a plurality of analog electrical signals, determine a plurality of DC offsets for the analog electrical signals, remove the DC offsets from the analog electrical signals to produce a plurality of DC-free analog signals, and convert the DC-free analog signals into a plurality of DC-free digital signals, and a DSP unit coupled to the frontend and configured to perform fiber dispersion compensation on the DC-free digital signals according to a dispersion value associated with the remote optical transmitter to produce a plurality of DC-free compensated digital signals, and add the DC offsets to the compensated digital signals to produce a plurality of DC-restored compensated digital signals.