Dispersion managed thulium-doped fiber laser mode-locked by the nonlinear loop mirror

Abstract Intracavity dispersion management in a passively mode-locked thulium-doped all-fiber laser, based on a nonlinear optical loop mirror (NOLM) saturable absorber is reported. Fundamental soliton and stretched pulse soliton generation are demonstrated, when the oscillator operates with anomalous net dispersion. Gaussian pulses with a duration of 253 fs and 26.4 nm spectral bandwidth centered at wavelength of 1967 nm were generated with a fundamental pulse repetition frequency of ~15.8 MHz. In soliton mode-locking regime the oscillator delivering optical solitons with a 3 dB spectral width of 7.96 nm and duration of 675 fs. To the best of our knowledge, this is the shortest fundamental soliton generated from thulium-doped fiber laser with all anomalous dispersion based on a nonlinear fiber loop mirror saturable absorber reported till date.