High-performance and wideband amplifier using bismuth-oxide-based EDF with cascade configurations

We demonstrate high-performance and wideband-bismuth-oxide-based erbium-doped fiber amplifiers (BI-EDFAs) with multi-stage configurations. Cascade configurations that gain flattening filters and isolators inserted between the doped fibers are applied in order to suppress amplified spontaneous emission (ASE). As a result of the optimization of the fiber length, the gain characteristics of the two-stage BI-EDFAs were improved in extended L-band region. The BI-EDFAs for four-channel coarse wavelength division multiplexing (CWDM) systems ranging from 1550–1610 nm are then presented. Three-stage configurations are applied, and a gain of 20 dB and an output power of 20 dB m are simultaneously achieved with practical pumping condition.