Optimal design of optically gain-clamped L-band erbium-doped fiber amplifier

Abstract

We theoretically investigate the optimal design of optically gain-clamped (GC) L-band (1570–1610 nm) erbium-doped fiber amplifier (EDFA), in order to achieve constant gain with minimum gain variation in the presence of dynamic input power variation or add/drop of optical channels, in terms of single- and multiple-channel schemes. The lasing-wavelength channel at either 1565 or 1610 nm for optically gain-clamping operation of such L-band GC-EDFAs in terms of different clamping-loop attenuation are examined. In addition, the characteristic measurements of such L-band GC-EDFAs using either a saturation tone or multiple channels are compared. From good gain-clamping capability point of view, the 1610-nm lasing channel with 15-dB loop attenuation is the best selection to offer large gain-clamping dynamic ranges of both input channel power and channel count with good channel gain variation and fairly low noise figure characteristics.