Gain enhancement of L-band EDFA by using residual pump power in a three-stage configuration

This paper presents an idea of using residual pump power for implementation of low-noise and high-gain L-band erbium-doped fiber amplifiers (EDFAs). A single pump laser is employed to pump the first-stage EDFA, which serves as a low-noise preamplifier, in the proposed three-stage EDFA system. The residual pump power unabsorbed by the preamplifier is directed to pump the subsequent EDF. Experimental results show that gain enhancement of up to 8 dB with respect to conventional EDFAs can be achieved by using the proposed low-noise EDFA.