Improvement of peak power of dissipative soliton resonance pulse in a thulium-doped fiber laser

Single pulse energy and pulse width can be theoretically increased indefinitely without pulse-breaking in a dissipative soliton resonance pulse (DSR) generated from a mode-locked fiber laser when the peak power is keeping in a certain value. But in some applications, both high pulse energy and high peak power are needed in one single pulse. To improve the peak power of the DSR pulse, the characteristics of DSR pulses were investigated and found that the position of the gain fiber is a factor to influence the peak power and the pulse width. Here, we demonstrate a thulium-doped mode-locked fiber laser operating in the DSR regime with a nonlinear amplifying loop mirror (NALM). When changing the position of the gain fiber, the peak power of DSR pulse could be improved from 0.38 W to 1.42 W with the same pump power. This approach provides a method for increasing the pulse energy and efficiency in mode locked fiber lasers, which may meet some special application.