High-Stability Sub-200 fs Diode-Fiber Hybrid Laser With Continuously Tunable and Programmable Repetition Rate

This work demonstrates a high-stability femtosecond fiber laser hybrid system, integrating a gain-switched diode (GSD) laser seed with nonlinear filtering, achieving both wide-range programmable repetition rate tuning (500 kHz to 10 MHz) and sub-200 fs (pedestal-free) pulse output. Through the incorporation of a fiber Bragg grating (FBG) filter matched precisely to the central wavelength of the GSD, spectral tailing components are effectively suppressed, resulting in improved temporal contrast and coherence. The optimized nonlinear spectral broadening extends the bandwidth to 21 nm, and subsequent dispersion compensation achieves a pedestal-free compressed pulse width of 120 fs. Furthermore, low-frequency phase noise is stabilized below -80 dBc/Hz through rubidium atomic clock locking. This all-fiber Hybrid system serves as a versatile platform for programmable micromachining, dynamic imaging, and ultrafast spectroscopy.