We report a compact, self-starting dispersion-managed mode-locked thulium-doped fiber oscillator that delivers 2.6 nJ pulses at 2 µm with a repetition rate of 250 MHz. The average output power and spectral bandwidth of the pulses reach impressive values of 648 mW and 103 nm, respectively. The generated pulses are near linearly chirped, capable of linearly compressing to 74 fs in a normal dispersion fiber after power attenuation. Using a nonlinear fiber compression scheme can even compress the pulses to 29 fs (4.3-cycle). The remaining pulse energy is 1.15 nJ, and the corresponding peak power is estimated as 39.4 kW. To the best of our knowledge, this is the first demonstration of nonlinearly compressing the pulse of a 2 µm fiber oscillator to the sub-5 cycle regime. Such a few-cycle fiber laser could be an ideal candidate source for short-wavelength mid-infrared frequency metrology and molecular spectroscopy applications.

中文翻译：

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从锁模的掺有Tm的光纤激光器产生几个周期的脉冲

我们报告了一种紧凑的，自启动的色散管理的锁模th掺杂光纤振荡器，该振荡器以2 µm的频率提供2.6 nJ脉冲，重复频率为250 MHz。脉冲的平均输出功率和频谱带宽分别达到648 mW和103 nm的惊人值。产生的脉冲接近线性chi，在功率衰减后，能够在正常色散光纤中线性压缩至74 fs。使用非线性光纤压缩方案甚至可以将脉冲压缩到29 fs（4.3周期）。剩余的脉冲能量为1.15 nJ，相应的峰值功率估计为39.4 kW。据我们所知，这是第一个将2 µm光纤振荡器的脉冲非线性压缩至5周期以下状态的演示。