Subchannel photonic routing, switching and protection with simplified upgrades of WDM optical networks

摘要

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.

主权项

1. An optical subchannel muxponder that can transmit optical signals among a plurality of nodes interconnected by one or more fiber optic cables to form an optical network, the optical subchannel muxponder comprising:
(a) a subchannel mapper that can map each of a plurality of client signals to a corresponding subchannel within or across a plurality of ITU channels, wherein each ITU channel in the plurality of ITU channels has a predefined ITU frequency and a corresponding plurality of subchannels, and wherein each subchannel has an associated frequency with a predetermined offset from the predefined ITU frequency of the subchannel's corresponding ITU channel; (b) one or more lasers that can be tuned to generate modulated client signals at frequencies associated with each subchannel; (c) a multiplexer that can combine the modulated client signals for transmission onto the fiber optic cables of the optical network; and (d) either (i) a client signal multiplexer that can combine a plurality of client signals into a single higher-rate signal that can be mapped to a distinct subchannel, or (ii) a client signal inverse multiplexer that can divide a client signal having a data rate into a plurality of signals including a first signal that can be mapped to a subchannel of a first ITU channel, and a second signal that can be mapped to a subchannel of a second ITU channel different from the first ITU channel.