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Abstract

The present invention provides a bidirectional wavelength division multiplexed optical communication network useful in numerous network configurations. The network includes a bidirectional optical waveguide carrying counter-propagating wavelength division multiplexed optical signals each including plural channels. Several optical nodes are positioned along the bidirectional optical waveguide, each of which includes an optically-amplified bidirectional optical add-drop multiplexer. Each bidirectional optical add-drop multiplexer includes channel selectors for selecting at least one optical channel from each of the counter-propagating WDM optical signals. Each optical node further includes at least one optical transmitter for supplying an optical channel to be added by the bidirectional optical add-drop multiplexer to the bidirectional optical waveguide and at least one optical receiver for receiving an optical channel dropped from the bidirectional optical waveguide by the bidirectional add-drop multiplexer. Preferably, each optical node includes a bidirectional optical service channel transmitter and receiver and a network control element. Through measurement of optical launch powers and optical amplifier gain, the optical power levels of the optical channels are controlled to within a specified range. The bidirectional optical systems of the present invention can be used to create flexible network topologies that are easily expandable to include additional optical nodes and have particular application in metropolitan area networks.

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First Claim