POLARIZATION INSENSITIVE DOUBLE-PATH TWO-STAGE EDFA

摘要

PURPOSE: A polarization insensitive double-path two-stage EDFA(Erbium-doped fiber amplifier) is provided to remove polarization sensitiveness of a gain flattening filter and an amplifier while having a high gain and a low noise figure. CONSTITUTION: An input end(1) receives signal light. An isolator(2) passes forward signal light while interrupting a backward proceed to prevent a noise due to reflection. A pump light source(3) generates pump light. A wavelength selection combiner(4) separates the signal light from the pump light or combines the signal light with the pump light. An FRM(Faraday Rotator Mirror)(8) is attached to a second erbium doped optical fiber(7) for reflecting the signal light and the pump light proceeded a first erbium doped optical fiber(5) and the second erbium doped optical fiber by rotating the signal light and the pump light at an angle of 90 deg. A circulator(6) outputs the amplified signal light reflected from the FRM. A GFF(Gain Flattening Filter)(10) is inserted into the second erbium doped optical fiber for flattening gain of an amplifier amplified in the first and second erbium doped optical fibers.