A branching unit branches a first wavelength-multiplexed optical signal input through a first transmission line, the first wavelength-multiplexed optical signal including first and second optical signals, A wavelength selection unit receives the branched first wavelength-multiplexed optical signal branched by the branching unit, receives a second wavelength-multiplexed optical signal including a third optical signal in the same band as that of the first optical signal and a fourth optical signal in the same band as that of the second optical signal through a second transmission line, outputs a third wavelength-multiplexed optical signal including the first and fourth optical signals optical to a third transmission line and output the third optical signal. A multiplexing unit outputs a fourth wavelength-multiplexed optical signal in which the branched first wavelength-multiplexed optical signal branched by the branching unit and the third optical signal output from the wavelength selection unit are multiplexed to a fourth transmission line.

A network element includes a client port configured to receive a signal for transmission; a line port configured to transmit the signal to a far end via Optical Transport Network (OTN); circuitry configured to communicate one or more of a fault and a status associated with the signal to the far end via OTN overhead. The circuitry configured to communicate can be for the fault and utilizes one or more Tandem Connection Monitoring (TCM) layers in the OTN overhead. The circuitry configured to communicate can be for the status and utilizes one or more of Optical Data Unit (ODU) Performance Monitoring (PM) and one or more Tandem Connection Monitoring (TCM) layers.

A system identifies rogue optical network units (ONUs) on a passive optical network that uses time and wavelength division multiplexing. An optical line terminal (OLT) is configured to recognize the occurrence of errors on the upstream transmission over the network. When those errors reach a predetermined threshold, the OLT attempts to identify potential rogue ONUs by controlling the ONUs to tune to different wavelengths. The OLT first controls the ONUs to transmit on a first wavelength. The OLT then iteratively divides the ONUs into multiple groups, each group being assigned a different wavelength for upstream transmission. The OLT them monitors upstream transmission to determine which group of ONUs is exhibiting rogue behavior. This process is repeated until a small group of ONUs is isolated as a potential rogue. The potentially rogue ONUs are individually analyzed and one or more ONUs is positively identified. The system then tunes the rogue ONUs to one or more isolated channels so as not to interfere with communication by other ONUs.

In general, the present disclosure is directed to a transmitter optical subassembly (TOSA) module for use in an optical transceiver or transmitter that includes a magnetically-shielded optical isolator to minimize or otherwise reduce magnetization of TOSA components. An embodiment of the present disclosure includes a TOSA housing with magnetic shielding at least partially surrounding an optical isolator, with the magnetic shielding reflecting associated magnetic energy away from components, such as a metal TOSA housing or components disposed therein, that could become magnetized and adversely impact the magnetic flux density of the magnetic field associated with the optical isolator.

An example system includes a first network device having first circuitry. The first network device is configured to perform operations including receiving data to be transmitted to a second network device over an optical communications network, and transmitting first information and second information to the second device. The first information is indicative of the data, and is transmitted using a first communications link of the optical communications network and using a first subset of optical subcarriers. The second information is indicative of the data, and is transmitted using a second communications link of the optical communications network and using a second subset of optical subcarriers. The first subset of optical subcarriers is different from the second subset of optical subcarriers.

Concepts and technologies for multi-lane optical transport network recovery are provided herein. In an embodiment, a system includes a multi-lane optical transceiver. The multi-lane optical transceiver can include a transmitter optical sub-assembly, a receiver optical sub-assembly, and a controller that includes a processor and a memory that stores computer-executable instructions that, in response to execution by the processor, cause the processor to perform operations. The operations can include detecting an optical interruption event corresponding to an optical lane within a multi-lane optical path. The operations can further include instantiating an optical protocol alarm based on the optical interruption event. The operations can further include generating an optical protocol message based on the optical protocol alarm. The operations can further include instructing a peer multi-lane optical transceiver to alter optical transmission along the multi-lane optical path based on the optical protocol message.

In general, the present disclosure is directed to a transmitter optical subassembly (TOSA) module for use in an optical transceiver or transmitter that includes a magnetically-shielded optical isolator to minimize or otherwise reduce magnetization of TOSA components. An embodiment of the present disclosure includes a TOSA housing with magnetic shielding at least partially surrounding an optical isolator, with the magnetic shielding reflecting associated magnetic energy away from components, such as a metal TOSA housing or components disposed therein, that could become magnetized and adversely impact the magnetic flux density of the magnetic field associated with the optical isolator.

An optical module includes a plurality of ports configured to connect to a multi-fiber cable that includes transmit fibers and receive fibers therein for the plurality of ports; a detector for each of the plurality of ports configured to detect loss of signal at a port level; and a processor configured to perform automatic power reduction only for affected ports of the multi-fiber cable that have a detected loss of signal. The multi-fiber cable can be an MPO cable.

An optical branching/coupling device includes: a first optical branching unit that splits first light with a first and a second wavelength, and outputs second light and third light; a wavelength selector that receives the second light, receives fourth light with a third wavelength, output fifth and sixth light, one of the fifth light and the sixth light including an optical signal of the first wavelength of the second light and including the fourth light, and the other including an optical signal of the second wavelength; a first light switch that receives the fifth light and the sixth light, output one of the fifth light and the sixth light as seventh light, and output the other as eighth light; and a second light switch that receives the third light, receives the eighth light, and outputs the third or the eighth light that have been input as ninth light.

An optical module includes a plurality of ports configured to connect to a multi-fiber cable that includes transmit fibers and receive fibers therein for the plurality of ports; a detector for each of the plurality of ports configured to detect loss of signal at a port level; and a processor configured to perform automatic power reduction only for affected ports of the multi-fiber cable that have a detected loss of signal. The multi-fiber cable can be an MPO cable.