Mid-infrared supercontinuum generation in a single-mode thulium-doped fiber amplifier

Mid-infrared supercontinuum (SC) generation in a thulium fiber amplifier is reported. The system delivered an average output power of 2.37 W in a spectral band of ∼(1.75–2.7) μm which is, to the best of our knowledge, the highest average power of SC generated from a single-mode Tm-doped fiber. For wavelengths longer than 2.4 μm, the output power was as high as 0.49 W, constituting almost 21% of the total output power. A 10 dB spectral flatness in the wavelength interval ranging from 1.95 to 2.52 μm (570 nm span) with a corresponding (calculated) spectral power density greater than 3 mW nm −1 is demonstrated. Amplification in both emission bands of Tm 3+ ions, as a way to effectively enhance SC generation towards longer wavelengths, is also discussed.