A wavelength selective bidirectional isolator for access optical networks

Abstract

A wavelength selective bidirectional 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 experience different phase retardation so that wavelength-dependent polarization states are obtained for bidirectional beams. As an example, a (1.49 μm, 1.31 μm) wavelength selective isolator is proposed, which means only 1.49 μm light can propagate along one-direction while the opposite wave is just for 1.31 μm light. Over 60 dB optical isolation is obtained by selecting suitable wave plate thickness and orientation. This interesting isolator may have promising applications in access optical networks.