Systems and methods include managing optical spectrum in an optical network utilizing a flexible grid where each channel in the optical network has a center frequency and utilizes a plurality of bins to define spectral width, wherein each channel's occupancy on the optical spectrum is enumerated by its center frequency and plurality of bins.

Systems and methods are provided for reducing interference when optical signals are added. One embodiment includes a method for adding an optical channel for communicating data and having a bandwidth within an optical spectrum for transmission along an optical link of an optical network. The method includes creating a lower frequency holding zone having a lower frequency bandwidth adjacent to the bandwidth of the added optical channel and including at least one lower frequency sub-slice having a power spectral density that varies throughout the lower frequency sub-slice. Also, the method includes creating a higher frequency holding zone having a higher frequency bandwidth adjacent to the bandwidth of the added optical channel and including at least one higher frequency sub-slice having a power spectral density that varies throughout the higher frequency sub-slice. The lower frequency holding zone and the higher frequency holding zone are dynamically configured with respect to fiber and channel requirements.

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).

A network is provided with a plurality of nodes connected to one another. At least one node of the plurality of nodes include one or more transponders. For example, the transponders may be configured to receive optical signals having a first set of wavelengths at a first degree of a plurality of degrees in the at least one node. The transponders may convert the received optical signals into electrical signals, and then regenerate optical signals by generating, based on the electrical signals, optical signals having a second set of wavelengths. The node may further include one or more switches configured to route the regenerated optical signals to one or more of the plurality of degrees of the at least one node.

In order to provide a submarine optical transmission system that utilizes multiple wavelength bands, the submarine branching apparatus is provided with: a first demultiplexing part for demultiplexing a wavelength-multiplex optical signal input from a first terminal station into a first wavelength-multiplex optical signal and a second wavelength-multiplex optical signal; an optical add-drop part for outputting at least a third wavelength-multiplex optical signal included in the first wavelength-multiplex optical signal to a second terminal station, and for outputting a fifth wavelength-multiplex optical signal by multiplexing at least a fourth wavelength-multiplex optical signal included in the first wavelength-multiplex optical signal with a wavelength-multiplex optical signal input from the second terminal station; and a first multiplex part for multiplex the second wavelength-multiplex optical signal with the fifth wavelength-multiplex optical signal input from the optical add-drop part and outputting the resulting signal to a third terminal station.

Switching technology may be incorporated into various systems, components, and/or architectures in a fiber optic network to promote network reconfigurability and design flexibility. A signal access unit comprises an input, an output, an access port, a switch arrangement including a switch, and a controller. The switch optically couples the input to the output and not to the access port when in a first configuration, and optically couples the access port to at least one of the input and the output without optically coupling the input and the output together when in a second configuration. The controller is configured to receive an indication of a selected wavelength and to operate the switch arrangement to change the switch between the first and second configurations based on the indication of the selected wavelength.

An optical module includes a first multiplexer/demultiplexer and an optical receiver. The first multiplexer/demultiplexer is configured to receive a first optical signal from the second network device, separate a second optical signal having a first wavelength from the first optical signal, and transfer the second optical signal to the optical receiver. The first multiplexer/demultiplexer is further configured to transfer a third optical signal that is separated from the first optical signal and that has a wavelength other than the first wavelength to the third network device. The optical receiver is configured to receive the second optical signal.

Systems and methods include managing optical spectrum in an optical network utilizing a flexible grid where each channel in the optical network has a center frequency and utilizes a plurality of bins to define spectral width, wherein each channel's occupancy on the optical spectrum is enumerated by its center frequent and plurality of bins.

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.

A wavelength multiplexing communication system includes a master station apparatus and a plurality of slave station apparatuses. The master station apparatus includes a wavelength multiplexing communication unit that performs wavelength multiplexing communication with the plurality of slave station apparatuses by wavelengths the number of which is equal to or less than the number of the plurality of slave station apparatuses using an optical signal of a wavelength in a first wavelength group and an optical signal of a wavelength in a second wavelength group. The slave station apparatuses include an optical communication unit that performs communication of the main signal with the master station apparatus by an optical signal of a wavelength in the first wavelength group, which is different from a wavelength in the first wavelength group used by another slave station when the main signal communication is performed in the host slave station apparatus, and performs communication of a signal other than the main signal with the master station apparatus by an optical signal of a wavelength in the second wavelength group, which is a wavelength same as a wavelength used by another slave station apparatus when the main signal communication is not performed in the host slave station apparatus.