Broadband supercontinuum generation in a telecommunication fibre pumped by a nanosecond Tm, Ho: YVO₄ laser

Broadband supercontinuum (SC) generation in a telecommunication fibre [8/125-μm single mode fibre (SMF) and 50/125-μm multimode fibre (MMF)] directly pumped by a nanosecond Q-switched Tm, Ho : YVO₄ laser is demonstrated. At a 7-kHz pulse repetition frequency (PRF), an output average power of 0.53 W in the 1.95-2.5-μm spectral band and 3.51 W in the 1.9-2.6-μm spectral band are achieved in SMF and MMF, respectively (the corresponding optic-to-optic conversion efficiencies are 34.6% and 73.7%). The output spectra have extremely high flat segments in the range 2070-2390 nm and 2070-2475 nm with neglig ible intensity variation (less than 2%). The SC average power is scalable from 2.1 to 4.2 W by increasing the PRF from 5 to 15 kHz, while maintaining pump power. Compared with the input pump pulse, the output SC pulse width is broadened, and no split is found. The stability of the output SC power has been monitored for a week and the fluctuations being less than 6%.