A method for protection switching includes receiving an optical signal
from a transponder coupled to a client and optically splitting the signal
to a first output and a second output. The first output is coupled by a
first optical add-drop multiplexer to a first optical fiber, and the
second output is coupled by a second add-drop multiplexer to a second
fiber. The method further includes selecting one of the output signals
for the working channel, and communicating the selected output signal to
an optical network. During communication of the selected output signal to
the optical network, the method includes monitoring for a failure
condition in the optical network and, if the failure condition is
detected, selecting the other output signal as the working channel and
communicating the new selected output signal.