Compact optical circulator for optical fiber transmission

An optical circulator for near IR radiation was developed for optical transmission systems. This circulator consists of a 45 degrees Faraday rotator using a YIG single crystal and two Glan-Taylor prisms. It has four nonre-ciptocai and two reciprocal ports. Using reciprocal ports for bidirectional transmission systems with multi-mode fibers, which do not conserve light polarization, this circulator can receive any polarized light. Insertion losses of 1.5-2.3 dB among four nomeeiproeal ports were obtained at 1.32-microm wavelength. An insertion loss of 0.66 dB was estimated when nonpolarized light is transmitted, using one nonreciprocal and one reciprocal port at. 1.32-microm wavelength.