Provided are techniques, devices and systems that enable updating of a reportable parameter table database when a reconfigured optical communication path is formed by switching performed by a branching unit in an undersea optical communication transmission system. A processor may obtain system attributes of each respective segment of a number of segments of the reconfigured optical communication path from a first end point to a second endpoint. The system attributes of each respective segment of the number of segments may be evaluated from the first end point to the second endpoint of the reconfigured optical communication path. A reportable parameter table may be generated based on the evaluated system attributes that includes a listing of operational and structural parameters of system from the first endpoint to the second endpoint of the reconfigured optical communication path.

An upstream (US) optical line terminal (OLT) for a passive optical network having at least one downstream (DS) optical network unit (ONU). The OLT generates a trigger signal indicating a need to receive at least one US burst having a shortened codeword for a first forward error-correction (FEC) code. Based on the trigger signal, the OLT transmits a DS message instructing the ONU to transmit an US burst having a shortened codeword. The OLT receives and decodes the US burst having the shortened codeword using the first FEC code. During periods of high bit-error rate, the shortened codewords increase the ability of the OLT to decode the US bursts and keep communications from the ONU alive. The OLT can use the decoded US bursts to measure BER and, if appropriate, instruct the ONU to use a different FEC code.

An example optical switch includes a plurality of input ports and a plurality of output ports, a cross-connect fabric having one or more inputs, one or more outputs, and a device to selectively cross-connect the inputs with the outputs. The optical switch includes an integrated fast optical switch comprising a first input, a first output, and a second output, wherein the first input is connected to a first one of the outputs of the cross-connect fabric, and wherein the integrated fast optical switch has a switching time that is less than a switching time of the cross-connect fabric to switch the first input between the first output on a path to a first output port of the plurality of output ports and the second output on a path to a second output port of the plurality of output ports.

Disclosed herein are methods and systems for generating and/or obtaining at least one loading policy for a transmission line segment that is currently operating, the at least one loading policy comprising a combination of loading parameters for one or more types of loading management operations associated with the transmission line segment. At least one of the loading policies may be activated on a network element of the transmission line segment. Upon receiving a loading request to change a spectral loading pattern of the transmission line segment, current loading data of the transmission line segment and loading parameters from the activated loading policy may be obtained and used to generate a loading response. A signal containing the loading response may be sent to the network element, the signal configured to cause the network element to change the spectral loading pattern of the transmission line segment based on the loading response.

An optical end terminal in which protection switching is implemented by using (i) the optical data receiver thereof for detecting a path failure and (ii) the optical data transmitter thereof for signaling the detected path failure to the protection-switching circuit. In an example embodiment, the optical data receiver is configured to detect a path failure based on the presence of certain data-recovery errors. The optical data transmitter is operatively connected to the optical data receiver and configured to generate an in-band dither tone of a predetermined frequency in response to such failure detection. The protection-switching circuit is configured to (i) detect dither tones in the optical signals passing therethrough and (ii) connect the optical data receiver to the protection path instead of the working path in response to detecting the dither tone of the predetermined frequency.

There is provided an optical network comprising first and second PONs, each including an OLT; one or more ONUs; and an optical splitter downstream of the OLT and upstream of the one or more ONUs. The splitter includes a plurality of inputs, one of the inputs being coupled to the OLT, and a plurality of outputs, each of the ONUs being coupled to one of the outputs. The optical network further includes an optical switch configured to switch the optical network from a first configuration to a second configuration in response to a fault being detected on the first PON. The second PON's splitter has a spare output that is uncoupled in the first configuration; and the first PON's splitter has a spare input that is: uncoupled in the first configuration, and coupled to the spare output of the second PON's splitter in the second configuration.

In one example, a first Provider Edge (PE) node is configured to communicate with a second PE node through a packet-switched network and with a third PE node through the packet-switched network. The first PE node communicates with a fourth PE node via the second PE node. The fourth PE node is configured to communicate with the second PE node over a working path through a time-division multiplexing transport network. The first PE node exchanges, with the fourth PE node, protection information. Based on exchanging the protection information, the first PE node communicates with the fourth PE node via the third PE node. The fourth PE node is further configured to communicate with the third PE node over a protection path through the time-division multiplexing transport network.

A method is presented for supporting SNCP over a packet network connecting to two SDH sub-networks and transporting one or more SDH paths that are SNCP-protected in both SDH sub-networks. The packet network connects to each of two sub-network interconnection points by a working path and a protection path. The packet sub-network may provide the same type of path protection as an SDH sub-network using SNCP, while avoiding bandwidth duplication.

The present invention includes novel techniques, apparatus, and systems for optical WDM communications. Tunable lasers are employed to generate respective subcarrier frequencies which represent subchannels of an ITU channel to which client signals can be mapped. In one embodiment, subchannels are polarization interleaved to reduce crosstalk. In another embodiment, polarization multiplexing is used to increase the spectral density. Client circuits can be divided and combined with one another before being mapped, independent of one another, to individual subchannels within and across ITU channels. A crosspoint switch can be used to control the client to subchannel mapping, thereby enabling subchannel protection switching and hitless wavelength switching. Network architectures and subchannel transponders, muxponders and crossponders are disclosed, and techniques are employed (at the subchannel level/layer), to facilitate the desired optical routing, switching, concatenation and protection of the client circuits mapped to these subchannels across the nodes of a WDM network.

A communication device including a first communication device and a plurality of second communication devices in an optical access system in which a first communication device and the plurality of second communication devices perform communications with each other under a time division multiple access scheme includes an Ethernet controller configured to implement the communications as Ethernet (registered trademark) communications, and a link failure processing unit configured to output, in response to reception of a link failure notification for notifying occurrence of a link failure in the communications from the first communication device, a termination instruction to terminate data transmission when the communication device is performing the data transmission to the first communication device, and a start instruction to start the data transmission after recovery from the link failure when the communication device is not performing the data transmission to the first communication device.