A Tandem-Pumped, Tunable Thulium-Doped Fiber Laser in the 2.1 μm Wavelength Region

Laser sources operating in the 2.1 μm region will benefit many applications, including environment monitoring [1], remote sensing, medical surgery and pumping nonlinear frequency conversion process [2]. Here, we present a continuously-tunable thulium(Tm)-doped fiber laser (TDFL) operating at the important 2.1 μm region, which is tandem-pumped by another TDFL at 1908 nm.