An apparatus for management of a spectral capacity of a wavelength division multiplexing, WDM, system includes at least one pair of transmission fibers provided for transporting optical signals. Each transmission fiber of a transmission fiber pair is connected to a first port of an optical circulator having at least two additional ports and adapted to transmit an incoming optical signal entering one of its ports via its next port. WDM subsystems configured with counter-propagating assignable wavelengths are connected to associated ports of the optical circulator of the apparatus.

An optical transmission system includes a transmitting node that transmits wavelength light of an operational path to an optical waveguide, and a receiving node that receives the wavelength light from the optical waveguide. The transmitting node includes a light source that generates spontaneously emitted light and a wavelength selector that generates and outputs dummy wavelength light from the spontaneously emitted light generated by the light source. The receiving node includes an extractor that extracts spectral data of the dummy wavelength light passed in the optical waveguide. The optical transmission system further includes an obtainer that obtains a band state of the operational path from the spectral data of the dummy wavelength light extracted by the extractor.

Disclosed herein are systems and methods for neighbor discovery for any network transport layer; including a network element comprising: a processor, an interface connected to a network having a control channel, and instructions that, when executed by the processor, cause the network element to: generate a discover message comprising a message identification, a discovered node ID, and a discovered interface ID; send a first signal comprising the discover message over the control channel to a second network element; and receive a second signal comprising an acknowledgment message from the second network element over the control channel, the acknowledgment message being one of a positive acknowledgment message and a negative acknowledgment message; and wherein receipt of the positive acknowledgment message indicates that contents of the discover message were matched by the second network element, and receipt of the negative acknowledgment indicates that there was at least one mismatch in the contents.

An optical network and a method of use are herein disclosed. The optical network comprises a fiber optic line, two or more ROADMs, and an orchestrator comprising a processor and a non-transitory computer-readable medium storing processor-executable instructions that, when executed, cause the processor to: receive an operation to execute, the operation being a loading of a first optical service on the fiber optic line by a local ROADM; determine a status of a downstream ROADM as being available; reserve the downstream ROADM for the loading of the first optical service by preventing the downstream ROADM from loading a second optical service on the fiber optic line and disabling one or more control block of the downstream ROADM, thereby preventing the one or more control block from adjusting a configuration of the downstream ROADM; and load the first optical service on the fiber optic line.

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.

An optical transport network (OTN) node including a plurality of optical circuit switches (OCSs), each OCS being a respective degree of the OTN node, at least two of the OCSs including an input port configured to be connected to a respective optical transport fiber outside of the OTN node, at least one first output port connected to a first switching layer, and at least one second output port connected to a second switching layer. The first and second switching layers have different levels of granularity, such as but not limited to a wavelength switched layer, a band switched layer or a fiber switched layer.

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.

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.

A large number of degrees for relays of optical signals transmitted via optical paths in the degrees is secured. A wavelength cross-connect device 20A performs a relay by splitting optical signals from respective degrees indicated by reference numerals 40l, 40h, 40m, 40q, each of the degrees being provided by optical fibers, via respective optical couplers and outputting the split optical signals to output sides of the plurality of degrees via respective WSSs 23a to 23d. As the optical couplers, variable couplers 27a to 27d whose respective splitting ratios, each of which is a ratio of optical signal power losses in splitting an optical signal, are variable are used. The wavelength cross-connect device 20A includes a control unit 26 that performs control to change the splitting ratios in such a manner as to eliminate an imbalance among OSNR margins of the output sides of the degrees in which a plurality of optical paths transmitting the split optical signals extend. The control unit 26 calculates the margins for the respective optical paths transmitting the split optical signals via the variable couplers 27a to 27d, for each of the output sides of the degrees. The control unit 26 performs control to, based on respective smallest margins of the degrees in all the margins, change the splitting ratios of the variable couplers 27a to 27d in such a manner as to eliminate an imbalance between the margins of the degrees.

Example embodiments of the present invention relate to optical wavelength directing devices used to construct compact optical nodes.