Improved fluorescence characteristics of rare earth co-doping heavy-metal fluoride glasses for optical fiber amplifier

Er-doped heavy-metal fluoride glass, because of its wider emission bandwidth around 1500 nm, which spans the most important communications window, now has been investigated as one of the most promising materials for wide-band optical fiber amplifier, which would be of great value in the future wavelength division multiplexing (WDM) optical fiber communication system. However, one drawback of Er-doped fluoride glass is its low branching ratio leading to 1.55 /spl mu/m amplification under 980 nm excitation which is adopted for a low noise amplifier. Now this problem is expected to be solved by the rare earth co-doping technique. It has been proved that Ce co-doping into Er-doped fluoride glasses significantly improved the fluorescence quantum yield for the 1.55 /spl mu/m transition with 980 nm excitation. The Ce,Er co-doped fluoride glass is expected to be a new candidate material of a fiber amplifier for WDM.