Highly efficient 978 nm diode-pumped erbium-doped fibre amplifier with 24 dB gain

Abstract

We report an Er3+-doped fibre amplifier pumped with a strained GaInAs/AlGaAs quantum-well diode laser operating at 978 nm. Efficient optical coupling of the diode laser pump was achieved with a wedge-tipped fibre. An optical gain of 24 dB at 1535 nm was obtained with only 6.2 mW of pump power, corresponding to a gain of 3.9 dB/mW of pump power. This is the highest efficiency for a fibre amplifier achieved thus far.