The application discloses an optical isolator having an input and an
output, the optical isolator comprising a phase retardation plate
positioned at the input, and an optical rotator positioned between the
phase-retardation plate and the output, the isolator comprising a Faraday
rotator positioned between a first polarizer and a second polarizer. The
application also discloses a process comprising rotating a polarization
of an optical signal using a phase retardation plate, and following the
rotation of the polarization of the optical signal using a phase
retardation plate, further rotating the polarization of the optical
signal using an optical rotator.