Faraday compensator of reciprocal optical anisotropy utilizing a polarization ring interferometer

It is shown that a polarization ring interferometer containing a Faraday cell can be used to compensate the reciprocal anisotropy in round-trip optical circuits. It is established theoretically and experimentally that, unlike the case of conventional Faraday mirrors, the quality of the restoration of the polarization in a compensator based on a polarization ring interferometer is practically independent of the Faraday rotation angle. A deviation of the Faraday rotation angle from 45° leads only to an additional power loss. The novel compensators can be used in fiber-optic circuits with a wideband light source or with several sources having different wavelengths. Pis’ma Zh. Tekh. Fiz. 25, 57–63 (May 26, 1999)