Yb:fiber laser-based, spectrally coherent and efficient generation of femtosecond 1.3-μm pulses from a fiber with two zero-dispersion wavelengths.

We report, to the best of our knowledge, the first experimental characterization of spectral coherence properties of wavelength conversion inside photonic crystal fibers with two zero-dispersion wavelengths (TZDWs) and demonstrate a low-noise femtosecond 1.3-μm source employing the TZDW fiber and a 1.3-W, 240-fs Yb:fiber amplifier as the seeding source. Theoretical investigation shows that pulse evolution in our TZDW fiber source is dominated by parametric amplification seeded by self-phase modulation broadening which efficiently converts the pump energy into two new wavelength bands in a deterministic manner, leading to low noise and coherent excitation of femtosecond pulses tunable in the 1.3-μm spectral region, with up to 3 nJ of pulse energy at 32% of conversion efficiency.