全光纤高功率被动锁模掺铥光纤激光器

High power all-fiber passively mode-locked thulium-doped fiber laser

利用非线性光环形镜(NOLM)的可饱和吸收特性实现了可自启动的2μm全光纤高能量被动锁模掺铥光纤激光器。当泵浦功率大于3W时,激光器工作在连续或不稳定脉冲运转状态;泵浦功率达到4.69W后,输出为自启动锁模脉冲,重复频率4.26MHz,中心波长2 061.5nm,光谱半极大宽度18.1nm,平均输出功率8.8mW;继续增加泵浦功率到最大值7.56W,可以得到中心波长2 062.2nm、光谱半极大宽度17.1nm、斜率效率为6.2%、脉冲宽度和能量分别为424fs和65.6nJ的稳定锁模脉冲。这是目前已报道的在未经放大情况下脉冲能量最高的2μm锁模脉冲光纤激光器。

A self-starting 2 μm a fiber passively mode-locked Tm3＋-doped fiber laser based on nonlinear loop mirror （NOLM）was demonstrated.The laser operated at a continuous wave or unstable pulses regime after reaching the launched pump power of 3 W.Self-starting mode-locked pulses centered at 2 061.5 nm with an FWHM of 18.1 nm and an average output power of 8.8 mW were achieved when the launched pump power increased to 4.69 W.Continuously increasing to the maximum launched pump power of 7.56 W,stable mode-locked pulses centered at 2 062.2 nm with a FWHM of 17.1 nm were produced at a slope efficiency of 6.2%.The pulses operated at the repetition rate of 4.26 MHz with a single pulse energy up to 65.6 nJ and a pulse width of 424 fs.To the best of our knowledge,this was the first demonstration on mode-locked fiber laser based on NOLM at 2μm region with the highest single pulse energy.