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

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 dynami c input power variation or add/drop of optical channels, in terms of single - and multiple-channel schemes. The lasing-wavelength channel at either 156 5 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 satu ration tone or multiple channels are compared. From good gain-clamping capa bility point of view, the 1610-nm lasing channel with 15-dB loop attenuatio n 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. (C) 2001 Elsevier Science B.V. Al l rights reserved.