Ultrashort pulse duration and broadband dual-comb laser system based on a free-running passively mode-locked Er-fiber oscillator

摘要

We have demonstrated pulse duration compression and wavelength extension to a dual-comb free-running passively mode-locked Er-fiber oscillator. At first, the pulse duration of the dual-comb ultrashort pulses from the oscillator is nonlinearly compressed to ～50 fs by fiber amplifiers. Then, a dual-comb supercontinuum laser source with broadband wavelength band from 1.0 to more than 1.75 μm is achieved when the compressed pulses are used to pump highly nonlinear fibers. At last, utilizing the dual-comb supercontinuum source as the seed for spectral-selected Yb-fiber amplifiers, sub-100 fs ultrashort pulses are obtained at 1.0 μm. This free-running dual-comb fiber laser system can provide ultrashort pulses with sub-100 fs pulse duration at 1.0 μm, 1.5 μm and broadband supercontinuum covering 1.0 to more than 1.75 μm, so it can be potentially deployed in dual-comb applications such as absolute distance measurement, coherent anti-stokes Raman spectroscopy, and mid-infrared differential frequency generation.