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 εm 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.
© 1981 Optical Society of America
M. Shirasaki, H. Kuwahara, and T. Obokata, "Compact polarization-independent optical circulator," Appl. Opt. 20, 2683-2687 (1981)