All-optical gain-clamped L-band erbium-doped fiber amplifier with two feedback-loop lasing wavelengths

We experimentally investigate an optically gain-clamped (GC) L-band (1570 to 1600 nm) erbium-doped fiber amplifier (EDFA). Two lasing wavelengths in the optical feedback loop, 1568 and 1600 nm, are separately used for gain clamping with different loop attenuations. The characteristics of the EDFA with single-channel and simulated multichannel operations are examined and compared. We find that the 1568-nm lasing light is a better selection for an L-band GC EDFA to offer good channel gain with satisfactory noise figure characteristics.