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.

This disclosure describes devices and methods related to multiplexing optical data signals. A method may be disclosed for multiplexing one or more optical data signals. The method may comprise receiving, by a dense wave division multiplexer (DWDM), one or more optical data signals. The method may comprise combining, by the DWDM, the one or more optical data signals. The method may comprise outputting, by the DWDM, the combined one or more optical data signals to one or more wave division multiplexer (WDM). The method may comprise combining, by the one or more WDM, the combined one or more optical data signals and one or more second optical data signals, and outputting an egress optical data signal comprising the combined one or more optical data signals and one or more second optical data signals.

In the elastic optical network, there has been the problem that processing steps increase that are required to re-optimize client signals to be concentrated; therefore, an optical network controller according to an exemplary aspect of the present invention includes reallocation detection means for monitoring an operation status of at least one of an optical communication channel and an optical node device that constitute an optical network, and determining, based on the operation status, whether or not to reallocate a client signal accommodated in an optical path set in the optical network; design-candidate exclusion means for designating, as a design exclusion object, at least one of the optical communication channel and the optical node device that are associated with an optical path targeted for reallocation that accommodates the client signal that the reallocation detection means has determined to reallocate; optical path design means for determining an alternative route for the optical path targeted for reallocation from among routes with the exception of the design exclusion object; traffic reference means for determining the client signal to be reaccommodated in an optical path on the alternative route, referring to demand traffic accommodated in the optical path targeted for reallocation; and line concentration design means for constituting line-concentration traffic in which traffic having been allocated to the alternative route and the demand traffic are concentrated, wherein the traffic reference means determines a reallocation optical path in which an optical path candidate with number of occupied wavelength slots increasing is excluded from optical path candidates on the alternative route, and the optical path design means determines wavelength allocation of the reallocation optical path so as to accommodate the line-concentration traffic.

A wavelength-setting auxiliary device according to an embodiment of the inventive concept includes an optical wavelength analyzer configured to transmit a test signal having a first wavelength to an optical line terminal, and to execute a central wavelength detection algorithm based on a result of detecting power of a return signal for the test signal to set optical wavelength information of a tunable optical module, and a connector connected to the tunable optical module for interfacing data transmitted between the optical wavelength analyzer and the tunable optical module.

This disclosure describes devices and methods related to multiplexing optical data signals. A method may be disclosed for multiplexing one or more optical data signals. The method may comprise receiving, by a dense wave division multiplexer (DWDM), one or more optical data signals. The method may comprise combining, by the DWDM, the one or more optical data signals. The method may comprise outputting, by the DWDM, the combined one or more optical data signals to one or more wave division multiplexer (WDM). The method may comprise combining, by the one or more WDM, the combined one or more optical data signals and one or more second optical data signals, and outputting an egress optical data signal comprising the combined one or more optical data signals and one or more second optical data signals.

Devices and methods for bypassing a defective component in a combining network relaying respective upstream and downstream signals between a head end and a plurality of subscribers. The devices and methods may preferably redirect the upstream signal without redirecting the downstream signal using a wavelength-dependent filter.

An optical communication system of the present invention switches a communication wavelength from a current communication wavelength to a auxiliary communication wavelength when an abnormality occurs in a communication wavelength between a station-side device and any one of a plurality of subscriber devices. Further, this optical communication system switches a communication wavelength used for communication between the subscriber device and the station-side device that perform communication using the auxiliary communication wavelength from the auxiliary communication wavelength back to the current communication wavelength when communication is recovered from an abnormality in the current communication wavelength.

The present invention includes novel techniques, apparatus, and systems for optical WDM communications. Tunable lasers are employed to generate subcarrier frequencies representing subchannels of an ITU channel to which client signals can be mapped. Client circuits can be divided and combined before being mapped, independent of one another, to individual subchannels within and across ITU channels. Subchannels may be independently routed to a single subchannel receiver filter, such that each subchannel detected at the receiver may come from a different source location. 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 client circuits mapped to these subchannels across the nodes of a WDM network. Subchannel hopping may also be used to increase the optical network security.

An optical transmission apparatus includes an input unit, a demultiplexing unit, a measurement unit, and a switching unit. The input unit inputs a first multiplexed signal and a second multiplexed signal each obtained by multiplexing a plurality of optical signals having different wavelengths. The demultiplexing unit demultiplexes the first multiplexed signal and the second multiplexed signal by wavelength. The measurement unit measures qualities of a plurality of optical signals obtained by demultiplexing the first multiplexed signal and qualities of a plurality of optical signals obtained by demultiplexing the second multiplexed signal. The switching unit performs switching between the first multiplexed signal and the second multiplexed signal to be output to a subsequent stage based on a result of measurement by the measurement unit.

A communication device is connected to a wavelength-multiplexed optical ring network, and performs communication by performing time-division multiplexing on optical signals at each wavelength. In a case where a control signal transmitted from the master communication device is not received in a predetermined period, the communication device instructs a scheduler unit to suspend transmission of data at a failure wavelength that is the wavelength at which the host communication device has been determined not to be operating properly, also instructs the scheduler unit to transmit the data stored in the buffer of the failure wavelength at another wavelength, and suspends allocation of new data to the buffer of the failure wavelength. Thus, the delay in transmission of data at the failure wavelength can be shortened.