Method and apparatus for compensating for first-order Polarization Mode
Dispersion in an optical transmission system. An apparatus has a
polarization controller for transforming polarization components of an
optical signal carried by the optical fiber into orthogonal polarization
states, a variable delay line for introducing a variable differential
time delay between the polarization states and for producing an output
optical signal that is compensated for PMD in the optical fiber, and a
feedback unit for adjusting the polarization controller and the variable
delay line to compensate for variations in the PMD of the optical fiber,
the feedback unit including apparatus for generating a plurality of
independent control signals to independently control actuators of the
polarization controller and the variable delay line. The invention
provides for a reduction in response time of the actuators and a
reduction in complexity of an algorithm used to control the apparatus.