High⁃Power, 770-nm Femtosecond Laser Based on Spectral Pre-Modulated 1540-nm Fiber Laser with Nonlinear Compression

We demonstrate an 80-MHz, 350-mW, 120-fs, 770-nm femtosecond laser, based on a nonlinear compressed 1540-nm femtosecond fiber laser. The home-built 1540-nm fiber laser delivering the 80-MHz, 2.69-W, 269-fs laser pulses, was realized by employing the spectral pre-modulation and pre-chirp management inside the Er/Yb co-doped fiber power amplifier. Subsequent nonlinear fiber pulse compression stage was utilized to further nonlinearly compress the pulse duration to 128 fs, based on the Gaussian assumption. Detailed numerical simulation was also implemented to investigate the optical dynamics of the nonlinear compression process. A 0.5-mm-thick fan-out periodically poled lithium niobate (PPLN) crystal was finally utilized to generate the frequency-doubled, 350-mW, 770-nm laser pulses with a 120-fs pulse duration, based on the Gaussian assumption.