Abstract
The elimination of a back-reflected transverse electric (TE) mode traveling in a transverse-magnetic (TM)-mode optical isolator with a Si guiding layer was investigated. The optical isolator had an optical interferometer that included a polarization-dependent reciprocal phase shifter in one of the arms. By adjusting the length of the reciprocal phase shifter, the interferometer prevented the back-reflected TE mode from coupling into an input port of the isolator. An extinction ratio of more than 32.0 dB was obtained against the back-reflected TE mode at a wavelength of 1.57 µm.