Analysis of generation of high-energy dissipative solitons in all-normal-dispersion mode-locked photonic crystal fiber laser

In this research, an all-normal-dispersion mode-locked photonic crystal fiber laser (MLPCFL) is simulated. Three types of large-pitch PCFs with a small value of self-phase modulation coefficient are introduced and their fundamental characteristics are numerically investigated. They are then employed in the laser cavity and the performance of MLPCFL using these three different large-pitch PCFs is compared. According to the simulation results, as the hole-to-hole distance gets larger, the pulse spectrum profile changes from M-shape to parabolic and the temporal width of the pulses is also increased. Additionally, the simulation demonstrates that the presented laser has the potential to generate pulses with an energy of 450 nJ, if a 5 m length of passive PCF with Ʌ= 20 µm (Ʌ is hole-to-hole distance) is incorporated into the laser cavity. The results reveal that, by inserting a 1 m-long Yb-doped PCF with Ʌ= 20 µm at the output port of the laser, it becomes possible to generate pulses with an energy of 45 μJ and a peak power of 2.47 MW. The chirped output pulses from the amplifier are compressed after passing through the dispersion delay line and resulting in a reduction of the FWHM to 150 fs.