Generation of Wavelength Tunable MIR Frequency Comb Based on Yb-doped Fiber Laser

摘要

We report the generation of mid-infrared (MIR) frequency comb working at 184 MHz based on Yb-doped fiber laser system. The scheme pumped by high-power supercontinuum pulses was demonstrated firstly. Supercontinuum pulses from two fibers with different dispersion properties were examined. With a photonic crystal fiber (PCF) having normal dispersion properties, a tunable wavelength range of 2.9-4.7 μm was achieved. With another PCF having zero dispersion at 1040 nm, a maximum power of 1.34 mW was observed at 3.9μm. The high coherence of the MIR pulses generated with this scheme was verified experimentally, and a fringe visibility of 0.90 was observed. Next, a MIR comb centered at 4.5 pm was realized pumped by Raman soliton, with an average of 1.32 mW and a spectral FWHM of 63 nm. The coherence was verified by measuring the beat note with the help of a quantum cascade laser.