An example node includes a receiver, a switch circuit, and a transmitter. The receiver is configured to receive a first modulated optical signal including a first plurality of optical subcarriers, and supply a plurality of data streams based on the first plurality of optical subcarriers. Each of the data streams is associated with a corresponding one of the plurality of optical subcarriers. The switch circuit is configured to receive the data streams, and supply the data streams to a plurality of switch outputs. The transmitter is configured to receive the data streams, and supply a second modulated optical signal based on the data streams. The second modulated optical signal carries a second plurality of optical subcarriers. Each of the second plurality of optical subcarriers is associated with a corresponding one of the data streams.

In an example method, network traffic transmitted between a plurality of network nodes via a communications network is monitored. Subsets of the network traffic are ranked according to one or more ranking criteria. A mesh network is deployed between the plurality of network nodes based on the ranking of the subsets of the network traffic. The mesh network includes a plurality of network links, where each network link communicatively couples a respective network node from among the plurality of network nodes to another respective network node from among the plurality of network nodes.

An example system includes a network switch and a plurality of server computers communicatively coupled to the first network switch. The network switch includes a first transceiver configured to transmit data according to a first maximum throughput, and each server computer includes a respective second transceiver configured to transmit data according to a second maximum throughput that is less than the first maximum throughput. The network switch is configured to transmit, using the first transceiver according to the first maximum throughput, first data including a plurality of optical subcarriers to each of the server computers. Each of the server computers is configured to receive, using a respective one of the second transceivers, the first data from the network switch, and extract, from the first data, a respective portion of the first data addressed to the server computer.

An example system includes a plurality of network nodes, each including one or more respective first transceivers configured to transmit data according to a first maximum throughput, and one or more respective second transceivers configured to transmit data according to a second maximum throughput that is less than the first maximum throughput. A first network node is configured to transmit, using a respective one of the first transceivers, first data including a plurality of optical subcarriers to two or more second network nodes according to the first maximum throughput, each optical subcarrier being associated with a different one of the two more other network nodes. The two or more second network nodes are configured to receive, using respective ones of the second transceivers, the first data from the first network node.

An example system includes a first network node, a second network node, and a third network node. The first network node is configured to generate a first optical subcarrier representing first data, and transmit the first optical subcarrier to the second network node. The second network node is configured to receive the first optical subcarrier from the first network node, generate a second optical subcarrier representing the first data, where the second optical subcarrier is different from the first optical subcarrier, and transmit the second optical subcarrier to the third network node.

[Problem] To improve the add/drop rates while suppressing the apparatus scale of the ROADM.

[Solution] ROADM includes a wavelength cross-connect portion connected to a plurality of degrees, and a transponder accommodation function portion configured to relay an optical signal of the wavelength cross-connect portion to a transponder, in which the transponder accommodation function portion is configured such that a plurality of elements E that are a plurality of wavelength selective switches including one input port receiving an optical signal from a direction of the wavelength cross-connect portion and a plurality of output ports transmitting an optical signal in a direction toward the transponder is cascade-connected in a plurality of stages, and a plurality of elements E positioned at the same stage of the plurality of stages of cascade connection, to which an optical signal is propagated from the same degree of the plurality of degrees of the wavelength cross-connect portion, are multiple-connected as one module.

A node configured to operate in an optical network includes P switching planes interconnected by an SS cross-plane switch, P>1; and N.sub.i degrees per switching plane P.sub.i where i=1 to P, each degree formed by corresponding degree components having R ports, wherein a first set of ports of the R ports is for intra-plane switching, a second set of ports of the R ports is for inter-plane switching, and a third set of ports of the R ports is for in-plane add/drop. S is greater than or equal to a sum of a number of degrees across all of the P switching planes. R is greater than or equal to a sum of the first set of ports, the second set of ports, and the third set of ports.

Submarine cable branching units with fiber pair switching configured to allow any number of trunk cable fiber pairs to access the optical spectrum any number of branch cable fiber pairs. Access to a particular branch terminal is not limited to predefined subset of the trunk fiber pairs. This approach allows fewer branch cable fiber pairs to be equipped in each branching unit, reducing system cost, simplifies system planning and provides flexible routing of overall trunk cable capacity.

Systems and methods for creating a spectrum assignment for use by an optical network element are provided. In one implementation, an optical network element may include line devices configured to communicate optical signals with external network elements along one or more degrees. The optical network element may also include add/drop devices configured to perform at least one of adding one or more optical channels to the optical signals and removing one or more optical channels to the optical signals. The line devices and add/drop devices are configured to receive control signals from a spectrum management controller, the control signals being configured to allocate a first spectrum assignment for routing the optical signals through the line devices and further configured to allocate a second spectrum assignment for routing the optical signals through the add/drop devices. For example, the second spectrum assignment may be different from the first spectrum assignment.

A system for in-service defragmentation may identify optical signals having wavelengths within a first predefined optical wavelength band for transition from a current channel to an alternate channel within the first band and may determine directions and amounts by which to move the wavelengths. The identified wavelengths in the first band may be slowly and deliberately drifted by the determined amounts, using multiple incremental adjustments, and converted to corresponding wavelengths in a second predefined optical wavelength band for transmission. During the transitions, the drifting optical signals in the second band may be combined with optical signals remaining in their current channels in the first band for transmission. Once the wavelength transitions are complete, the transitioned optical signals may be transmitted on their alternate channels in the first band. Collections of wavelength transitions that do not cross each other may be identified and may be performed substantially in parallel.