Waveguide Isolator With Phase Mismatch

A novel optical waveguide isolator constructed from mode convertors with unsuppressed phase mismatch is proposed. The troublesome requirement of phase matching for transverse electric (TE)-transverse magnetic (TM) mode conversion is eliminated without degradation on the performances. It is found that a kind of self-phase compensation phenomenon occurs during TE-TM mode conversion that facilitates the operation of the isolator. An isolator based on this mechanism is designed and simulated. An isolation of -24.4 dB is obtained.