Spectral dependence of the small-signal gain around 1.5 μm in erbium doped silica fiber amplifiers

A simple theoretical analysis of small-signal Er³⁺-doped silica fiber amplifier is presented, comparing the efficiency of the 800-, 980-, and 1500-nm pump bands, and demonstrating that wide bandwidth and high gains can be achieved simultaneously by a suitable choice of pump power and fiber length. The comparison shows that the 980- and 1500-nm pump bands have much the same efficiency in terms of dB/mW, and that the 800-nm pumped amplifier is able to produce high gains but at nearly an order of magnitude higher pump powers