Er/sup 3+/-doped fiber amplifier pumped by 0.98 mu m laser diodes

Abstract
The performance of an Er/sup 3+/-doped fiber amplifier pumped by 0.98 mu m InGaAs laser diodes (LDs) is reported. By using a fiber with low Er/sup 3+/ content and optimizing the fiber length, a maximum signal gain of 37.8 dB at 30-mW pump power was realized at a signal wavelength of 1.536 mu m. A maximum gain coefficient of 1.9 dB/mW at 14 mW pump power was achieved. It was found that the fiber amplifier pumped by the 0.98- mu m LDs is twice as efficient as that pumped by 1.48- mu m LDs, from the viewpoint of both required fiber length and the attained gain.