Compact polarization-independent optical circulator

This paper introduces a compact polarization-independent optical circulator for communications using multimode optical fibers. This circulator consists of two pairs of rutile prisms used as polarization separators, a YIG Faraday rotator, a ring-shaped magnet, and a quartz halfwave plate. Insertion losses of 2.3 dB including fiber connection losses and isolations of 32 dB at a wavelength of 1.3 epsilonm were obtained using this circulator, and stabilization of the semiconductor laser was confirmed. Details on the design, fabrication, and characteristics of this circulator are presented.