... .,ltd,skype:ruiktech,yhl(at)ruik-tech.com) 3port/4port polarization insensitive optical circulator has been always along with very excellent features: low insertion ... , Fiber optic LAN Systems. CATEGORY: 3port/4port polarization insensitive optical circulator components for Telecom Circulator --- 3-Port Circulator, 1310/1550 nm --- 4-Port Circulator, 1310/1550 nm Isolator/Hybrid --- Isolator ...