Fiber Optic Circulators, 3-port SM Optical Circulators|GLsun

 GLsun designs 1310/1550 nm single mode optical circulator, 3-port passive device that allows light signal  to travel in 1 port and exit from 2 ports direction. It may be used in many applications.

https://www.glsun.com/products-c12-optical-circulators.html