Polarization-independent waveguide optical isolator based on nonreciprocalphase shift

A polarization-independent waveguide optical isolator based on nonreciproca l interference is proposed in this letter. This design uses simultaneous TE and TM nonreciprocal phase shifts obtained from geometric asymmetry in hor izontal and vertical axes of waveguide cross section along with opposing tr ansverse and vertical magnetic fields in interferometer arms. A design to a chieve such an isolator is described. Both TE and TM nonreciprocal phase sh ifts comparable to the theoretical counterparts have also been experimental ly observed from a single waveguide.