Experimental measurements of solitary pulse characteristics from an all-normal-dispersion Yb-doped fiber laser

We demonstrate a solitary pulse output from an 8.3-MHz mode-locked Yb-doped fiber laser, operating entirely in the normal dispersion regime. The typical output hyperbolic-secant pulses have a 14-ps pulse width and a 1.2-mW average output power. The spectrum has steep band edges with a 6.1-nm width and a tunable center wavelength between 1050 and 1080 nm. Using a frequency-resolved optical gating setup, we show that the pulse intensity and phase profiles are consistent with a chirped soliton. Energy quantization is observed, thus demonstrating the non-parabolic nature of these pulses. The laser output is compressed to near the transform limit (approximately 430 fs).