Mid-infrared supercontinuum generation is demonstrated by using a 75 % germanium-doped silica fiber pumped by a 2 μm Q- switched thulium- doped fiber laser with pulse width of 50 ns. The free space coupling efficiency from the pump laser to the germanium-doped fiber is enhanced by fusion-splicing a 100~200 μm long multimode fiber. Length of germanium-doped fiber is optimized. Broadband supercontinuum generation ranging from 1.9 μm to 2.9 μm with 10 dB and 20 dB bandwidths of 950 nm and 980 nm, respectively. The 2.9 μm long wavelength limit is close to the record reported so far for highly germanium-doped fiber based supercontinuum generation sources.