1X2 Circulator is irreversible optical device, the optial path is unidirection: Port1 to Port2, Port2 to Port3. GB-Link Circulator with high isolation and low loss, it is widely used in OADM,Two-way pump system and Dispersion Compensation device./Circulator can be used to realize single fiber bidirection communication./Working with FBG, Circulator can separate signal from DWDM system.