An OSNR spectrum estimation apparatus includes an OSNR estimation unit configured to cause an optical node to estimate an OSNR of a predetermined transmission line using a probe light of a predetermined wavelength in a predetermined number of wavelength channels, the predetermined number being less than the number of all wavelength channels; and an OSNR spectrum calculation unit configured to calculate an OSNR spectrum of all the wavelength channels from OSNRs of the predetermined number of wavelength channels measured by the optical node.

A transmitter can include a laser operable to output an optical signal; a digital signal processor operable to receive user data and provide electrical signals based on the data; and a modulator operable to modulate the optical signal to provide optical subcarriers based on the electrical signals. A first one of the subcarriers carriers carries first TDMA encoded information and second TDMA encoded information, such that the first TDMA encoded information is indicative of a first portion of the data and is carried by the first one of the subcarriers during a first time slot, and the second TDMA encoded information is indicative of a second portion of the data and is carried by the first one of the subcarriers during a second time slot. The first TDMA encoded information is associated with a first node remote from the transmitter and the second TDMA encoded information is associated with a second node remote from the transmitter. A second one of the subcarriers carries third information that is not TDMA encoded, the third information being associated with a third node remote from the transmitter. A receiver and system also are described.

An apparatus includes a reconfigurable optical add/drop multiplexer (ROADM) having an input port to receive a first optical signal from a second device. The ROADM also includes a first wavelength selective switch (WSS), in optical communication with the input port, to convert the first optical signal into a second optical signal, a loopback, in optical communication with the first WSS, to transmit the second optical signal, and a second WSS, in optical communication with the loopback, to convert the second optical signal to a third optical signal and direct the third optical signal back to the second device via the input port.

A fiber diagnostics system facilitates testing, troubleshooting, tracking, identifying and logging information pertaining to fiber optic networks and their associated elements, including aggregated upstream and downstream statistics and trouble identification for all ports and services on the PON (Passive Optical Network), including Optical Line Networks and Optical Network Terminals (OLNs and ONTs). Traffic and network activities may be viewed as a whole or may be isolated to focus on specific networks, segments, WANs or LANs and individual client locations and devices, including devices residing on the customer premises beyond the point of demarcation.

The present subject matter relates to methods, systems, devices, circuitry and equipment providing for communication service to be transported between first and second networks and which monitors the communication service and/or injects test signals over two fiber cables. A first single fiber cable is used to interface the communication services between the first and second network. A second single fiber cable is used to monitor the communication services and/or inject signals. The circuitry comprises a plurality of input amplifiers, output amplifiers, and multiplexer switches between a plurality of port connectors. An SFP module is inserted in all ports, and the SFP modules connect to one or more fiber optic cables.

An unused path through which actual data is not transmitted in a long-distance redundant network can be appropriately detect, and this function is realized at low cost. A transmission unit 33 of optical transceivers 21a and 21b connected to each other by an optical fiber cable 22 in an optical transmission system 20 includes a laser 37 for emitting a laser beam serving as an optical signal P1 to the optical fiber cable 22, and an optical intensity control unit 35 for performing control to change the optical level of the optical signal of the laser beam. Each of the optical transceivers 21a and 21b includes a control unit 31 for superimposing each of an idle signal A1, an OAM signal O1, and an actual data signal D1 on an XGMII signal 31s and outputting this XGMII signal 31s to the transmission unit 33 that transmits the optical signal P1, and a signal determination unit 32 for determining unique information regarding each signal output to the transmission unit 33 and outputting a determination result signal 32s. The optical intensity control unit 35 performs control to change the optical level of the optical signal P1 on which a signal of the determination of each signal indicated by the determination result signal 32s is superimposed to different optical levels L1 to L3 between the signals.

Provided are a communication monitoring method and a communication monitoring apparatus capable of an operation of identifying a coated optical fiber regardless of a propagation direction of an optical signal even before communication between an OLT and an ONU is opened. The communication monitoring apparatus according to the present invention includes: an optical signal detection unit 31 configured to receive, as a received signal, at least one of a downlink optical signal transmitted from an OLT 21 or an uplink optical signal transmitted from an ONU 22; and a signal analysis unit 32 configured to detect a signal type and unique information of a transmission source from information included in the received signal, determine whether the received signal is the downlink optical signal or the uplink optical signal on the basis of the signal type, and determine that the unique information of the transmission source is unique information of the OLT when the received signal is the downlink optical signal and that the unique information of the transmission source is unique information of the ONU when the received signal is the uplink optical signal.

An example system includes a transceiver and a microcontroller. The microcontroller is configured to receive, from first and second network interfaces of the transceiver, a plurality of messages from a hub node and the leaf nodes. Each of the messages corresponds to a respective one of the ingress or egress data flows. The microcontroller is also configured generate a resource assignment map based on the messages. The resource assignment map includes pairings between a respective one of the ingress data flows and a respective one of the egress data flows, and, for each of the pairings, an indication of a respective network resource assigned to exchange the egress data flow of that pairing with a respective one of the leaf nodes. The microcontroller is also configured to generate a command to cause the transceiver to transmit the egress data flows in accordance with the resource assignment map.

Provided are a communication monitoring method and a communication monitoring apparatus capable of an operation of identifying a coated optical fiber regardless of a propagation direction of an optical signal even before communication between an OLT and an ONU is opened. The communication monitoring apparatus according to the present invention includes: an optical signal detection unit 31 configured to receive, as a received signal, at least one of a downlink optical signal transmitted from an OLT 21 or an uplink optical signal transmitted from an ONU 22; and a signal analysis unit 32 configured to detect a signal type and unique information of a transmission source from information included in the received signal, determine whether the received signal is the downlink optical signal or the uplink optical signal on the basis of the signal type, and determine that the unique information of the transmission source is unique information of the OLT when the received signal is the downlink optical signal and that the unique information of the transmission source is unique information of the ONU when the received signal is the uplink optical signal.

A performance monitor configured to unify at least two different signal-quality estimates into a single performance metric such that a systematic error associated with the performance metric can be approximately constant or smaller than a specified fixed limit over a significantly wider range of data-link conditions than that of a conventional performance metric of similar utility. In an example embodiment, the performance metric can be based on a weighted sum of two different SNR estimates, obtained from an error count of the receiver's FEC decoder and from a constellation scatter plot generated using the receiver's symbol decoder, respectively. Different weights for the weighted sum may be selected for different data-link conditions, e.g., using SNR thresholding, analytical formulas, or pre-computed look-up tables. The performance metric may be supplied to a control entity and considered thereby as a factor in a possible decision to trigger protective switching and/or a transponder-mode change.