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.

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.

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.

Optical transmission device is provided in one of a plurality of nodes in an optical network. Different carrier frequencies are respectively allocated to the plurality of nodes. The optical transmission device includes: transmitter, splitter and receiver. The transmitter generates a first subcarrier optical signal with a first subcarrier established on a low-frequency side of a first carrier frequency and a second subcarrier optical signal with a second subcarrier established on a high-frequency side of the first carrier frequency. The splitter splits an optical signal including the first subcarrier optical signal and the second subcarrier optical signal. The output of the splitter is guided to first and second adjacent nodes. The receiver recovers data carried by the first subcarrier and data carried by the second subcarrier from received optical signal. A difference between carrier frequencies of adjacent nodes corresponds to a bandwidth of the subcarrier.

A terminal node, an optical network and/or a method are described in which a first processor of a first optical protection switching module having a first optical switch, and a second processor of a second optical protection switching module having a second optical switch coordinate switching of the first optical switch and the second optical switch upon detection of a first failure by the first processor, or the detection of a second failure by the second processor. The first processor monitors optical signals received by a first line port to determine a first failure in a first working path at a first layer (e.g., physical layer) within an optical communication model. The second processor monitors the optical signals received by another line port to determine a second failure in the first working path at a second layer (e.g., optical layer) within the optical communication model.

[Problem] To provide a novel optical network which can be used as an in-vehicle optical backbone network and exhibits high capacity, low delay, low power consumption, low noise and low cost. [Solution] An optical network system, wherein: a signal processing unit 13 controls a light source 11, and generates an optical signal which includes an information portion to be read by one of the gateway units 5a, and a continuous light portion to be written thereby; a network control unit 15 generates an electrical signal which designates a gate y unit 5a and pertains to whether the information incorporated into the optical signal is to be read or written; and when designated by the electrical signal, each of the gateway units 5a transfers information to and from an electronic control unit 7, and reads information included in the corresponding optical signal or writes information in the continuous light portion, on the basis of the information included in the electrical signal about whether to read or write information.

This disclosure describes C and L band optical communications module link extender, and related systems and methods. An example method may include receiving, by a dense wave division multiplexer (DWDM) at a headend, one or more optical data signals over only an L band. The example method may also include combining the one or more optical data signals. The example method may also include outputting the combined one or more optical data signals to a first WDM at the headend. The example method may also include outputting, by a first WDM, the one or more optical data signals to an amplifier at the headend. The example method may also include amplifying, by the amplifier, the one or more optical data signals. The example method may also include outputting the amplified one or more optical data signals to a coexistence filter. The example method may also include outputting, by the coexistence filter, the amplified one or more optical data signals to an optical switch. The example method may also include outputting, by the optical switch, an egress optical data signal to a first fiber.

Provided is an optical communication device including: a first channel card configured to convert an input first signal into a first optical signal and output the first optical signal to any one of a first MUX/DEMUX connected to a first optical line and a second MUX/DEMUX connected to a second optical line; a second channel card configured to convert an input second signal into a second optical signal and output the second optical signal to any one of the first MUX/DEMUX and the second MUX/DEMUX; and a controller configured to monitor states of the first optical line and the second optical line to determine a MUX/DEMUX from which the first optical signal and the second optical signal are respectively output, from among the first MUX/DEMUX and the second MUX/DEMUX.

A terminal node, an optical network and/or a method are described in which a first processor of a first optical protection switching module having a first optical switch, and a second processor of a second optical protection switching module having a second optical switch coordinate switching of the first optical switch and the second optical switch upon detection of a first failure by the first processor, or the detection of a second failure by the second processor. The first processor monitors optical signals received by a first line port to determine a first failure in a first working path at a first layer (e.g., physical layer) within an optical communication model. The second processor monitors the optical signals received by another line port to determine a second failure in the first working path at a second layer (e.g., optical layer) within the optical communication model.

This disclosure describes devices and methods related to multiplexing optical data signals. A method may be disclosed for multiplexing one or more optical data signals. The method may comprise receiving, by a dense wave division multiplexer (DWDM), one or more optical data signals. The method may comprise combining, by the DWDM, the one or more optical data signals. The method may comprise outputting, by the DWDM, the combined one or more optical data signals to one or more wave division multiplexer (WDM). The method may comprise combining, by the one or more WDM, the combined one or more optical data signals and one or more second optical data signals, and outputting an egress optical data signal comprising the combined one or more optical data signals and one or more second optical data signals.