These components are used for fiber-optical data transmission in communication applications. Isolators allow light to pass through the fiber in only one direction; circulators are non-reciprocal elements that redirect light from connector to connector.
For Data Transmission
With the help of isolators, light can only be transmitted in a single direction through the fiber. Back reflections in the opposite direction are prevented to a large extent by higher attenuations. Polarization-independent and polarization-maintaining components are available.
Circulators are passive components that transmit an optical signal from gate 1 to gate 2, another signal from gate 2 to gate 3, and so forth. Polarization-independent and polarization-maintaining components are available.