2.1 μm Band Dissipative Soliton Resonance Mode-Locked Ho-Doped Tunable Fiber Laser

We report a 2.1 μm band mode-locked holmium-doped fiber (HDF) laser with tunable wavelength and pulse width in dissipative soliton resonance (DSR) region for the first time to our knowledge. A piece of HDF is pumped by a home-made 1.9 μm band fiber source, and a nonlinear-amplifying-loop-mirror structure is used to realize mode-locking operation with net anomalous dispersion. The repetition rate of pulse is 8.97 MHz. The pulse duration can be adjusted from 1.16 to 3.93 ns with the increase of pump power, while maintains a constant peak power. At the maximum pump power of 2.1 W, the pulse energy is up to 2 nJ. Moreover, the central wavelength is in the tunable range from 2054.4 to 2076 nm by appropriately adjusting the polarization controllers. We also explore the nonlinear correlation characteristic of DSR pulse by changing the length of high nonlinear fiber.