Enhanced tunable Raman soliton source between 1.9 and 2.36 μm in a Tm-doped fiber amplifier.

We demonstrate generation of widely tunable femtosecond pulses by utilizing the soliton self-frequency shift effect in a Tm-doped fiber amplifier, seeded by dispersion managed mode-locked Tm oscillator. The monochromatic soliton pulses with a duration of the order of 100 fs have been obtained and its wavelength can be adjusted continuously in the range of 1.9-2.36 μm by varying the pump power. The efficiency of Raman conversion is as high as 97% with output power up to 1.16 W. The experimental results are in good agreement with numerical simulations of pulse propagation in Tm-doped fiber amplifier.