Sub-200 fs, 344 MHz mode-locked Tm-doped fiber laser.

We demonstrate a compact, self-starting mode-locked thulium-doped fiber laser based on nonlinear polarization evolution (NPE), with a fundamental repetition rate of ∼344 and a pulse duration of ∼160. The generated pulses centered at ∼1975 have a maximum output power of ∼560, corresponding to a pulse energy of ∼1.63. To the best of our knowledge, the achieved repetition rate represents the highest value of fundamentally NPE mode-locked fiber lasers at ∼2µ, while the average output power is also higher than the previously reported 2 µm ultrafast single-mode fiber oscillators. The timing jitter in the integrated range [5 kHz, 10 MHz] and the integrated relative intensity noise in the range [10 Hz, 10 MHz] reach ∼35 and ∼0.009, respectively. Our high-performance laser is an ideal candidate for various applications, including mid-infrared frequency metrology and high-speed optical sampling.