ANALYSIS OF POLARIZATION-INDEPENDENT OPTICAL AMPLIFIERS AND FILTERS BASED ON POLARIZATION ROTATION IN PERIODICALLY ASYMMETRIC WAVE-GUIDES

Polarization rotation in periodically asymmetric passive and active waveguides is described theoretically; the analysis is based on the vector wave equation and analysis of the coupled mode equations. It is shown that these periodically asymmetric active waveguides can be employed as polarization independent optical amplifiers and that strictly polarization independent amplifiers require a rotation of an integer multiple of pi radians. An illustrating example of such an amplifier with a buried waveguide structure suitable for monolithic integration is analyzed. Polarization insensitive passive Bragg filters employing, in addition to the ordinary grating, a periodically asymmetric perturbation, are also considered, and polarization rotation in a distributed feedback laser amplifier filter is discussed.