Flattened dual-stage GC-EDFA using fiber-ring laser technique

A counter-propagating ring-laser cavity technique was demonstrated for gain-clamped and flattened erbium doped fiber amplifier. This technique was achieved by incorporating fiber Bragg grating at center wavelength 1554.88 nm with reflectivity 72.01%. A gain variation was maintained below 1.0 dB with maximum gain 15 dB and noise figure less 7 dB at pump power of 92 mW. Equalization with gain variation less than 2.0 dB can be obtained over a 12 nm wavelength range. A dual stage configuration has an added advantage where it is possible to achieve both high gain and low NF.