Ultra-short Wavelength Operation of a Thulium Doped Fiber Laser in the 1620–1660nm Wavelength Band

We present a tunable thulium-doped fiber laser (TDFL) incorporating a Tm/Ge co-doped fiber capable of accessing the U-band wavelength region (1620–1660nm). These results represents by far the shortest laser wavelengths so far for a TDFL.