Keywords:fiber laser, optical frequency comb, ultrashort pulse
Passively mode-locked fiber lasers are stable and practical ultrashort pulse laser sources. Recently, nano-carbon materials absorb a lot of attentions as a useful mode-locker. So far, we have been investigating the highly functional ultrashort pulse fiber laser sources and their applications. In this talk, we present our recent progress about our research, mainly on the optical frequency comb. In the NIR region, we demonstrated octave spanning coherent supercontinuum (SC) comb, and wavelength tunable comb. The output pulse from stabilized Er-doped fiber laser comb was amplified with similariton amplifier, and 1.0 - 2.0 um octave spanning coherent SC comb was generated with highly nonlinear fiber. Then the wideband wavelength tunable comb source was also demonstrated using nonlinear fiber techniques. It can be tuned continuously and arbitrary. We also developed MIR comb system based on ultrashort pulse fiber lasers. The output pulse from a passively mode-locked Yb doped fiber laser was amplified, and MIR comb was generated through DFG between 1.04 um and 1.35 um components. The high coherence was confirmed with RF beat measurement with QCL.