All-optical gain control for bidirectional optical add-drop multiplexer using ASE noise path through multi-port circulators
An all-optical gain control method for a bidirectional optical add-drop multiplexer using an amplified spontaneous emission noise path through multi-port circulators is reported. The device provides constant gain and low noise figure over a large input power range, has low crosstalk and removes Rayleigh backscattered and back-reflected light.