Integrated optical isolator and circulator using nonreciprocal phase shifters: a proposal.

In this paper, we propose an integrated optical isolator and circulator using nonreciprocal phase shifters combined with Y-branch couplers or hybrid couplers. They are not used in mode coupling between orthogonally polarized waves, which leads to reduce the fabrication tolerance. We present a design example using the guide structure of YIG film and GGG substrate.