Abstract: A communication system in which a master station device is connected to a plurality of slave station devices by an optical transmission line and a plurality of wavelengths are used to perform at least one of downstream communication and upstream communication. The master station device includes: a control unit that assigns a wavelength to be used in communication to the slave station device, and that generates a control signal for notifying the slave station device of the assigned wavelength; and an optical transmitter that transmits the control signal generated by the control unit to the slave station device. The slave station device includes an optical receiver and an optical transmitter that carry out communication with the master station device using the wavelength based on the control signal received from the master station device.

Abstract: Methods and systems for collision control during delay measurements in optical transport networks include scheduling delay measurements in time slices of a time window. At most, one delay measurement per time slice is scheduled and performed for each optical data unit (ODU) in an optical transport network (OTN).

Abstract: An optical communication apparatus includes a light receiving unit, a wavelength band determining unit and an estimating unit. The light receiving unit receives light which changes to predetermined wavelength bands in a predetermined cycle according to communication object information, for a predetermined light reception period. The wavelength band determining unit determines each wavelength band of the light received by the light receiving unit. The estimating unit estimates that a wavelength band of the light received by the light receiving unit is any one of the predetermined wavelength bands, in a case where said wavelength band determined by the wavelength band determining unit is not any one of the predetermined wavelength bands.

Abstract: A method for measuring asymmetry in propagation delay of first and second links which connect a first node to a second node of a communication network. The method comprises measuring (101) a round trip delay of the first link. The round trip delay can be measured by transmitting (102) a test signal from the first node to the second node over the first link and receiving a reply to the test signal from the second node over the first link. The method further comprises measuring (105) a round trip delay of the second link. The round trip delay can be measured by transmitting (106) a test signal to the second node over the second link and receiving a reply to the test signal from the second node over the second link. A difference in the propagation delay of the first link with respect to the second link is determined (109) using the measured round trip delays of the first link and the second link.

Abstract: A reference management apparatus includes a reference signal housing, a fixed length propagation device, an oscillator device, and a reference management computing device. The reference signal housing having a propagation signal output and a propagation signal input. The fixed length propagation device is coupled between the propagation signal output and the propagation signal input. The reference signal management computing device is coupled to the oscillator device and the propagation signal input.

Abstract: A first reconfigurable optical add/drop multiplexers (ROADM) and a second ROADM are connected by a primary light path and a protection light path. The first ROADM includes a first direction and a second direction, and the second ROADM includes a third direction and a fourth direction. The primary light path is coupled between the first direction and the third direction, and the protection light path is coupled between the second direction and the fourth direction. Transmissions on the primary light path are monitored, and when a problem is detected on the primary light path, the first and third directions are deactivated and the second and fourth directions are activated so that additional light signals are sent on the protection light path and not on the primary light path.

Abstract: A driving method of a light emitting device including visible light emitting elements is provided. In a first visible light communication mode, a first portion of the visible light emitting elements is driven and a second portion of the visible light emitting elements is idled for the first portion of the visible light emitting elements having a first current density. In a second visible light communication mode, each of the visible light emitting elements is driven so as to have a second current density. An illumination brightness difference of the light emitting device between the first visible light communication mode and the second visible light communication mode is smaller than 15%.

Abstract: A system for communication over a fiber link is disclosed. The system comprises a transmitter to transmit an information signal that comprises an information spectrum, and to transmit two spectrally inverted copies of the information spectrum over the predefined length of the fiber link, the two spectrally inverted copies corresponding to a first spectrum with a first center wavelength and to a second spectrum with a second center wavelength, the second spectrum being inverted relative to the first spectrum and the second center wavelength being different from the first center wavelength, and a receiver to receive the first spectrum and the second spectrum, and to estimate a phase rotation of the second spectrum relative to the first spectrum by comparing a first phase measured from the first spectrum with a second phase measured from the second spectrum.

Abstract: An active receiver structure that combines a large number of detectors without bandwidth penalty may provide a better signal-to-noise ratio (SNR) than conventional Radio Frequency over Glass (RFoG) networks. A transmission line receiver is used to combine a large number of optical detectors into a single radio frequency (RF) signal without a bandwidth penalty and a modest penalty in noise performance that results in an SNR that is much better than traditional optical combining techniques that are followed by a single detector. An optical multiplexer structure may be designed around the active splitter such that passive optical network (PON) operation is not impeded.

Abstract: There is provided a system and a method for determining an in-band noise parameter representative of the optical noise contribution (such as OSNR) on a polarization-multiplexed optical Signal-Under-Test (SUT) comprising two polarized phase-modulated data-carrying contributions and an optical noise contribution.

Abstract: An apparatus includes: a first measurer configured to measure first phase data indicating a temporal variation in a phase of a non-transferred signal that is an optical signal modulated by an optical phase modulation scheme and output from a transmitting device to an optical transmission path as the non-transferred signal; a second measurer configured to second phase data indicating a temporal variation in the phase of the optical signal transferred by the optical transmission path as a transferred signal on a side of a receiving device; a generator configured to generate differential data indicating a difference between the first phase data and the second phase data; and an extractor configured to use the differential data to extract, from the optical signal on the side of the receiving device, optical phase noise generated due to the optical transmission path.

Abstract: A Pulse Amplitude Modulated (PAM) optical device utilizing multiple wavelengths, features a communications interface having enhanced diagnostics capability. New registers are created to house additional diagnostic information, such as error rates. The diagnostic information may be stored in raw form, or as processed on-chip utilizing local resources.

Abstract: Embodiments are provided for scalable photonic packet fabric architectures using photonic integrated circuit switches. The architectures use compact size silicon photonic circuits that can be arranged in a combined centralized and distributed manner. In an embodiment, an optical switch structure comprises a plurality of core photonic based switches and a plurality of photonic interface units (PIUs) optically coupled to the core photonic based switches and to a plurality of groups of top-of-rack switches (TORs). Each PIU comprises a N×N silicon photonic (SiP) switch optically coupled to a group of TORs associated with the PIU from the groups of TORs, where N is a number of the TORs in each group. The PIU also comprises a plurality of 1×P SiP switches coupled to the group of TORs associated with the PIU and to the core photonic based switches, where P is a number of the core photonic based switches.

Abstract: An optical add/drop multiplexer incorporates an integrated receiver module and an integrated transmitter which are interfaced to an intervening electrical network to provide an add/drop/pass-through functionality. The receiver module incorporates a wavelength demultiplexer which is in turn combined with optical/electrical converters PIN photodiodes, and amplifiers on a per wavelength basis to output a plurality of parallel electrical signals in response to a common optical input. The transmitter module combines an integrated plurality of drive circuits and lasers for converting a plurality of parallel input electrical signals to a plurality of optical signals, on a per wavelength basis, which in turn are coupled via an optical wavelength multiplexer to a common output optical fiber. The interconnected electrical network, ring mesh or tree, can provide a reconfigurable electrical add/drop interface to other portions of the network.

Abstract: A method and apparatus for characterizing and compensating optical impairments in an optical transmitter includes operating an optical transmitter comprising a first and second parent MZ, each comprising a plurality of child MZ modulators that are biased at respective initial operating points. An electro-optic RF transfer function is generated for each of the plurality of child MZ modulators. Curve fitting parameters are determined for each of the plurality of electro-optic RF transfer functions and operating points of each child MZ modulator are determined using the curve fitting parameters. An IQ power imbalance is determined using the curve fitting parameters. Initial RF drive power levels are determined that compensate for the determined IQ power imbalance. The XY power imbalance is determined for initial RF drive power levels using the curve fitting parameters.

Abstract: In a communication network, a node at a subscriber premises includes an input/output (I/O) port, and a device for monitoring a subscriber premises. The device includes an upstream signal path including a first switch, a downstream signal path, and a controller having an input/output (I/O) port coupled to the I/O port of the node, and a first output port. The first switch is coupled to the first output port selectively to complete the upstream signal path.

Abstract: An optical module processes first FEC (Forward Error Correction) encoded data produced by a first FEC encoder. The optical module has a second FEC encoder for further coding a subset of the first FEC encoded data to produce second FEC encoded data. The optical module also has an optical modulator for modulating, based on a combination of the second FEC encoded data and a remaining portion of the first FEC encoded data that is not further coded, an optical signal for transmission over an optical channel. The second FEC encoder is an encoder for an FEC code that has a bit-level trellis representation with a number of states in any section of the bit-level trellis representation being less than or equal to 256 states. In this manner, the second FEC encoder has relatively low complexity (e.g. relatively low transistor count) that can reduce power consumption for the optical module.

Abstract: Systems and methods, for an in-band communication channel in an optical network, include adapting one or more client signals into a line signal for transmission to the second node, and utilizing line adaptation bandwidth of the line signal for the in-band communication channel. The in-band communication channel is operationally independent from the one or more client signals while concurrently being transported together over the line signal. The line adaptation allows a rate of the line signal to be independent of rates of the one or more client signals.

Abstract: A central node connected to a remote network node via a fiber optic link controls an antenna switch in the remote network node by controlling the DC bias current of the laser providing an optical transmission signal from the central network node to the remote network node via the fiber optic link. The remote network node converts the received optical transmission signal to an electrical transmission signal, and detects the DC level of the electrical transmission signal. If the detected DC level satisfies a predetermined condition, the remote network node connects the antenna port of the antenna switch, and thus the antenna, to a reception signal path of the remote network node. Otherwise, the remote network node connects the antenna port of the antenna switch, and thus the antenna, to a transmission signal path of the remote network node.

Abstract: A communication network including a master switch and one or more local switches is provided with a loop-back test device for in line loop-back testing. The local switches convey communication traffic between one another using one or more channels of a transmission medium and configuration information using an out-of-band channel of the transmission medium that is separate from the channels used to convey the communication traffic. The master switch includes an application that generates configuration information including loop-back connection information for configuring the out-of-band channel using at least one loop-back test device, transmits the generated configuration information to the loop-back test device using the out-of-band channel of the transmission medium, and conducts loop-back testing using the out-of-band channel.