A high-isolation polarization-independent optical quasi-circulator with a simple structure is proposed. A Porro prism is employed in this kind of device for what is believed to be the first time. Because a Porro prism is used, light beams pass back and forth through the main elements in the device. Thus the number of elements used in the device is decreased, and the device structure is simplified. A four-port quasi-circulator with monomode fibers was assembled and tested at the 1.55-µm wavelength. Its insertion loss, isolation, and return loss are ≦1.63 , ≧60 , and ≧55.6 dB , respectively.
© 1998 Optical Society ofAmerica
Lin-Dou Wang, "High-isolation polarization-independent optical quasi-circulator with a simple structure," Opt. Lett. 23, 549-551 (1998)