A Wavelength Selective Bidirectional Isolator

A wavelength selective optical isolator is proposed. Being different from conventional isolators, a well-designed wave plate is employed and works together with the Faraday rotator. Different wavelengths thus experiences different phase retardation so that wavelength-dependant polarization states are obtained for bidirectional beams. A (1.49 μm, 1.31 μm) wavelength selective isolator is demonstrated, which means 1.49 μm light only may propagate along one-direction why the opposite wave is only for 1.31 μm light. Over 60 dB optical isolation is obtained, which has promising applications in access optical networks.