Efficient Fibre Amplifiers Based on a Highly Er³⁺/Yb³⁺ Codoped Phosphate Glass-Fibre

Highly Er³⁺/Yb³⁺-codoped single-mode phosphate glass fibre is fabricated by the rod-in-tube technique. The performances of high-concentration Er³⁺/Yb³⁺-codoped phosphate glass fibre amplifiers are investigated and discussed. An efficient optical fibre amplifier with a gain of 12.6dB based on a 3.0cm long Er³⁺/Yb³⁺-codoped phosphate glass fibre is demonstrated under a dual-pump configuration with two 976nm fibre-pigtail laser diodes, which make it attractive for compact Er³⁺-doped fibre amplifiers. The obtained noise figures of signal wavelength from 1525 to 1565nm are less than 6.0dB. Gain saturation behaviour at 1535nm is also investigated, and the obtained saturation output power is larger than 10dBm.