Broadband emissions in Er/sup 3+/-Tm/sup 3+/ codoped tellurite glass fibre

In tellurite fibre EDFA, a gain-flattened amplification of 20 dB across a spectrum of 80 nm between 1530 and 1610 nm was demonstrated. By combining a tellurite fibre with Er/sup 3+/ dopant and a fluoride fibre with Tm/sup 3+/-ion dopant, the maximum gain flatness in two discrete S- and C+L bands is 113 nm. There is therefore an opportunity for developing an Er-Tm doped fibre with a seamless amplification bandwidth and flattened spectrum over 1410 nm to 1610 nm, which will be an ideal device for WDM.