Two-fiber optical shared protection ring with bi-directional 4/spl times/4 optical switch fabrics

A two-fiber optical shared protection ring has been demonstrated with a protection time under 7 ms, and a revert to normal time of under 2 ms. The number of 4/spl times/4 optical switch fabrics required to perform the protection switching has been reduced from two per optical channel to one. This reduction in number of optical switches is enabled by the inclusion of interleavers to separate and combine the two wavelengths of the duplex optical channel. The switches then operated in a bi-directional fashion, allowing the add and drop of an optical channel to propagate the same optical path through the switch. This leads to cost savings if eight interleavers or bandsplitters cost less than the 4/spl times/4 optical switch fabric technology being used.