Gain Characteristics of Er³⁺-Doped Phosphate Glass Fibres

An erbium-doped phosphate glass fibre has been drawn by the rod-in-tube technique in our laboratory. The gain for the Er³⁺-doped phosphate glass fibre with different pump powers and with different input signal wavelengths is investigated. The 2.2-cm-long fibre, pumped by a single-mode 980-nm fibre-pigtailed laser diode, can provide a net gain per unit length greater than 1.8dBcm. The pump threshold is about 50mW at the wavelength of 1534nm, and below 70mW at 1550nm. The gain linewidth of the Er³⁺-doped phosphate glass fibre is greater than 34nm and can cover the C band in optical communication networks.