The present invention is directed to a protection switch for use in a node
of a two-fiber optical shared protection ring. The two-fiber optical
shared protection ring propagates at least one bi-directional channel.
Each bi-directional channel includes a working first wavelength signal and
a working second wavelength signal. One fiber in the two-fiber optical
channel shared protection ring propagates the working first wavelength
signal in a first direction and the other fiber in the two-fiber optical
channel shared protection ring propagating the working second wavelength
signal in a second direction opposite the first direction. The switch
includes an N.times.N optical switch fabric system disposed in the node.
The N.times.N optical switch fabric includes 2N input/output (I/O) ports,
wherein N is four, or an integer multiple of four. Each optical switch
fabric is configured to switch at least one bi-directional channel. At
least N three-port optical devices are coupled to N of the I/O ports. Each
three-port optical device includes a bi-directional port coupled to an I/O
port. The bi-directional port is configured to propagate the at least one
bi-directional channel.
