Thulium Mode-Locked Fiber Laser

A Thulium fiber laser ring cavity is built and mode-locked. Four soliton spectrums are observed near 1900 nm. The pulse durations are estimated from the spectrums using a Fourier transform and from the soliton time-bandwidth product. The largest spectrum is near 550 fs in pulse duration. Kelly sidebands are noticeable on two of the spectrums and the sideband spacing is used to estimate the total dispersion of the cavity