Efficient pump wavelengths of erbium-doped fibre optical amplifier

By choosing pump wavelengths at which excited state absorption does not occur, efficient high gain operation of erbium-doped fibre amplifiers is possible. Practical pump wavelengths of 532nm and 980nm are identified as optimal, giving gains as high as 1.35 dB/mW and 2.2 dB/mW of pump at the two wavelengths, respectively.