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 M H z and a pulse duration of ∼ 160 f s . The generated pulses centered at ∼ 1975 n m have a maximum output power of ∼ 560 m W , corresponding to a pulse energy of ∼ 1.63 n J . To the best of our knowledge, the achieved repetition rate represents the highest value of fundamentally NPE mode-locked fiber lasers at ∼ 2 µ m , 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 f s 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.