The efficiency, small signal gain spectrum and noise characteristics o
f erbium-doped fluorozirconate fibre amplifier with a core diameter of
2.8 mum and a core-cladding refractive index difference of 40 X 10(-3
) are described. A gain coefficient of 3.4 dB/mW for 1.488 mum pumping
is obtained. Gain saturation occurs at 7 mW injected pump power. A ga
in of 27 dB obtained with 14 mW injected pump power gives an efficienc
y coefficient of 1.9 dB/mW in the gain saturation region.