High Power Er₃₊-Doped Fiber Amplifier Pumped by 1.48 µm Laser Diodes

An output power of 51 mW at a wavelength of 1.552 µm is obtained for the first time from an inGaAsP laser diode pumped Er₃₊-doped fiber amplifier. The pump power is 107 mW and the amplifier efficiency reaches 48%. The Er₃₊doping concentration is 630 ppm, and the fiber length is 20 m. The pump source is four inGaAsP laser diodes, which are operating at 1.45∼1.49 µm and are multiplexed using their polarizations and wavelengths. With simultaneous backward and forward pumping, the out put power is increased to 72 mW at a total pump power of 193 mW.