A network node (400) for use as a hub node of a network that further comprises one or more remote nodes, wherein the network node (400) is coupled to at least first and second connections (410, 412) for communication with one or more remote nodes, comprises a first band filter (403) adapted to separate a first aggregated signal (404) comprising a plurality of channel signals into a plurality of band signals (408.sub.1 to 408.sub.M). The network node (400) comprises a second band filter (405) and a third band filter (407) adapted to aggregate a plurality of band signals (408.sub.1 to 408.sub.M) into a second aggregated signal (406) comprising a plurality of channel signals and a third aggregated signal (413) comprising a plurality of channel signals, respectively. A switching module (409) is adapted to switch on a per-band granularity the plurality of band signals (408.sub.1 to 408.sub.M) between the first band filter (403) and either the second band filter (405) or the third band filter (407). The first band filter (403) may be adapted to aggregate the plurality of band signals (4081 to 408M) into the first aggregated signal (404); the second band filter (405) and a third band filter (407) may be adapted to separate the second aggregated signal (410) and third aggregated signal (412), respectively, into the plurality of band signals (408.sub.1 to 408.sub.M); and the switching module (409) may be adapted to switch on a per-band granularity the plurality of band signals (408.sub.1 to 408.sub.M) between either the second band filter (405) or the third band filter (407) and the first band filter (403).

An optical circuit includes: a multicast-and-select (MCS) switch and multiple optical selective devices coupled to output ports of the MCS switch. The selective devices may select a single optical channel by blocking some of wavelengths of light passing therethrough and passing at least one other wavelength. The selective devices may be wave blockers or tunable optical filters. The optical circuit further includes an optical amplifying array, wherein each amplifier has an input port optically coupled to one of the selective devices. At least some of the amplifiers have pump light ports for receiving at least a portion of the pump light from one or more laser pumps or from another of the optical amplifiers, wherein the pumps are capable of providing pump light sufficient to fully saturate all of the rare earth doped optical fibers in the array.

A flexible grid optical transmitter communicatively coupled to an optical network includes a coherent optical transmitter configured to generate a signal at a respective center frequency on an optical spectrum and spanning n bins about the respective center frequency, wherein n is an integer greater than 1, wherein the respective center frequency and the n bins are utilized to perform Operations, Administration, Maintenance, and Provisioning (OAM&P) functions. The respective center frequency and the n bins are specified to the coherent optical transmitter by a management system for the OAM&P functions. Each of the n bins can include a same arbitrary size, and the arbitrary size can be greater than or equal to 1 GHz and less than or equal to 12.5 GHz.

Example embodiments of the present invention relate to programmable ROADMs used to construct optical nodes. Example embodiments include wavelength switches and waveguide switches, wherein the waveguide switches may be programmed to direct wavelength division multiplexed optical signals to and from the wavelength switches.

An optical communications network comprises optical data links interconnected by add-drop nodes, the optical data links comprising data channels. The data channels are allocated into equal-sized bins. In response to a first data channel request between a given source-destination pair, one of the equal-sized bins is assigned to the data channel request. In response to requests for additional bandwidth for the same source-destination data channel request, unused channels within the assigned equal-sized bin are allocated to the data channel request. In response to subsequent data channel requests between different source-destination pairs, additional unallocated equal-sized bins are assigned to the subsequent data channel requests. In response to subsequent data channel requests when resource sharing for one equal-sized bin, data channels in the last equal-sized bin are assigned using the reverse channel assignment process. Reverse channel assignment can also be used for other bins as an option.

Example embodiments of the present invention relate to a software programmable reconfigurable optical add drop multiplexer (ROADM) comprising of a plurality of wavelength switches and a plurality of waveguide switches, wherein when the plurality of waveguide switches are set to a first switch configuration, the software programmable ROADM provides n degrees of an n-degree optical node, and wherein when the waveguide switches are set to a second switch configuration, the software programmable ROADM provides k degrees of an m-degree optical node.

Example embodiments of the present invention relate to programmable ROADMs used to construct optical nodes. Example embodiments include wavelength switches and waveguide switches, wherein the waveguide switches may be programmed to direct wavelength division multiplexed optical signals to and from the wavelength switches.

A flexible grid optical transceiver communicatively coupled to an optical network includes a coherent optical transmitter configured to generate a transmit signal at a first frequency/wavelength center and spanning a first one or more bins of optical spectrum; and a coherent optical receiver configured to receive a receive signal at a second frequency/wavelength center and spanning a second one or more bins of optical spectrum, wherein a size of each of the first one or more of bins and the second one or more of bins is based on a required roll off of a wavelength selective component in the optical network.

Method and apparatus of an optical routing system (ORS) capable of automatically discovering intra-nodal fiber connections using a test channel transceiver (TCT) are disclosed. ORS, in one embodiment, includes a set of reconfigurable optical add-drop multiplexer (ROADM) modules, intra-nodal fiber connections, add-drop modules, and a test module. The ROADM modules are able to transmit or receive optical signals via optical fibers. The intra-nodal fiber connections are configured to provide optical connections. The add-drop modules are able to selectively make connections between input ports and output ports. The test module containing TCT is configured to identify at least a portion of intra-nodal connections of the ROADM via a test signal operating with a unique optical frequency.

An optical switch, comprising: a first optical waveguide, a first optical add path, a second optical add path and a micro-ring resonator. The micro-ring resonator is operable to add a first optical signal at a preselected wavelength received from the first optical add path to the first optical waveguide to travel in a first direction through the first optical waveguide. The micro-ring resonator is further operable to add a second optical signal at the preselected wavelength received from the second optical add path to the first optical waveguide to travel in a second direction through the first optical waveguide opposite to the first direction. There is also provided an optical drop switch, an optical switching apparatus, an optical communications network node and an optical communications network.