Gain characteristics of Tm-doped fluoride fiber amplifier in S-band by dual-wavelength pumping

Abstract Optical properties and amplifier characteristics of Tm-doped fluoride fiber were investigated by pumping with 1.05 μm- and tunable L-band-lasers. Red-shift and improved gain in the S-band were observed by the pumping wavelengths in 1.55–1.64 μm in addition to the main 1.05 μm pump. The pump-power dependencies of gains were varied depending on the signal wavelengths in 1.44–1.52 μm region. The results were discussed with the laser level structures of the self-terminating transition of Tm 3+ ion for optimization of the S-band amplifier in the wavelength-division-multiplexing telecommunication.