All-optical gain-controlled bidirectional optical add-drop multiplexer

A new all-optical gain-controlled bidirectional optical add-drop multiplexer (BOADM) for use in single-fiber bidirectional networks is demonstrated. The BOADM uses amplified spontaneous emission (ASE) noise path through optical circulators (OCs) to achieve constant gain and low noise figure over a large range of input power. Moreover, the device has low crosstalk, is flexible, and removes Rayleigh backscattering and out-of-band ASE noise.