Er³⁺/Yb³⁺ Codoped Phosphate Glass Fibre with Gain per Unit Length Greater Than 3.0dB/cm

We experimentally study a novel fibre with high gain per unit length based on the homemade erbium--ytterbium codoped phosphate glass. The gain and noise characterizations with different pump powers at different wavelengths are investigated. The 1.8-cm-long fibre, dual-pumped by two single mode 980-nm fibre-pigtailed laser diodes, provides a gain per unit length greater than 3.0dB/cm and a noise figure less than 6.5dB. The gain saturation behaviour at 1535nm is obtained and the saturation output power (3dB compression) is greater than 5dBm.