Patent ID: 7035492

Claim:
A polarization-independent optical isolator/circulator comprising a two-arm interferometer each said arm comprising a non-reciprocal phase shifter comprising a first non-reciprocal phase shifter, a second non-reciprocal phase shifter and a half-wave retarder, said phase shifters being asymmetric in an axis orthogonal to the direction of light propagation; said phase shifters being disposed in series with respect to each other such that at least a portion of the light propagating through said first phase shifter will also propagate through said second phase shifter; said half wave retarder being disposed between said first and said second phase shifters, the slow axis of said half-wave retarder being at 450° to the direction of phase shifter asymmetry and orthogonal to the direction of light propagation; said first and second phase shifters being of a magneto-optic material, wherein the magnetization directions of the magneto-optical materials in said first and second phase shifters are different from one another and are orthogonal to the direction of phase shifter asymmetry and to the direction of light propagation.