TDFA/Raman hybrid amplifiers covering the entire S-band pumped by a single laser

Hybrid amplifier configurations are reported cascading one Raman and one or two Tm/sup 3+/-doped fiber stages, using a single pump at 1426 nm, allowing seamless amplification of the entire S-band (1460-1530 nm). Different configurations were studied, with gain over the entire band width and peak gain up to 24 dB. Noise figure as low as 7 dB was achieved.