GLsun optical circulator is a compact, high-performance lightwave component that routes incoming signals from Port 1 to Port 2, and incoming Port 2 signals to Port 3. It features on the smallest size, high isolation, low insertion loss, low polarization dependent loss (PDL), low polarization mode dispersion (PMD), and excellent environmental stability. Optical Circulator can be widely used for bi-direction transmission system,wavelength add/drop, dispersion compensation and fiber-optical sensor application.