GAIN AND NOISE PENALTY FOR DETUNED 980-NM PUMPING OF ERBIUM-DOPED FIBER POWER-AMPLIFIERS

The impact of altering the fiber length and pump wavelength on the gain and noise performance of erbium-doped fiber power amplifiers pumped in the 980-nm band is examined. A gain penalty of < 0.5 dB was experimentally observed over a 18-nm pump wavelength range. Theoretical analysis indicates that increasing the NA from 0.15 to 0.25 significantly improves the tolerance for a given gain penalty but has little effect upon noise figure. For a given fiber length, the noise figure increases by 0.1 dB for each 3 nm the pump wavelength deviates from 979 nm.