An EDFA-gain equalizer based on a Sagnac loop with an unpumped erbium-doped fiber

We have demonstrated an erbium doped fiber amplifier (EDFA) gain equalizer for flattening the amplified spontaneous emission gain spectrum using a Sagnac loop incorporated with a single-section unpumped erbium-doped fiber. The gain spectra output from the transmission port and the reflection port of the Sagnac loop are studied in detail. The absorption effect of unpumped erbium-doped fiber and the...