Multi-mode pumped amplifier using a newly developed 8-cm long erbium-doped phosphate glass fiber

A fiber amplifier with a net gain of 43dB at 1535nm and 21dB over the full C-band was demonstrated using a newly developed 8-cm long erbium-doped phosphate fiber excited with a 1 W 975nm multimode laser diode. A theoretical model was developed for multi-mode pumped amplifier using a very short fiber.