Ultra-wideband L-band EDFA using phosphorus co-doped silica-fiber

We have newly developed an L-band EDFA using phosphorus co-doped silica-based fiber. A 3dB bandwidth of 50.2 nm was achieved for single-stage operation in the wavelength range from 1564.4 to 1614.6 nm. In addition, the concatenated characteristics were evaluated through the loop transmission experiments, and we found that more than 40.6 nm bandwidth was achievable in the wavelength range from 1567.0 to 1607.6 nm after 4000 km transmission, which corresponds to 120 concatenations. This bandwidth was more than 8 nm larger than that of the conventional silica-based L-band EDFAs.