Compact optical circulator for near-infrared region

A compact Faraday-rotation 4-port circulator was developed for the near-infrared region. This circulator consists of an yttrium-iron-garnet Faraday rotator, biased by two permanent magnets, and two Glan-Taylor prisms. Insertion losses of 2.7–3.2 dB and isolation ratios of 13–28 dB among non-reciprocal ports were obtained at 1.15μm wavelength.