All-Fiber Thulium-Doped Mode-Locked Lasers Based on the Nonlinear Amplifying Loop Mirror

Abstract

We  report  on  thulium-doped  all-fiber  lasers  based on the nonlinear amplifying loop mirror and mode-locked by both a semiconductor saturable absorber (SESAM) and  single-walled  carbon  nanotubes (SWCNT).  An  intracavity  and  external dispersion management was realized with the aid of a passive germanium-silicate fiber.  SESAM  mode-locked laser  generates  as  short  as  230-fs  pulses with maximum  average  output  power  of  106 mW, corresponding to a 3.7 kW peak power and almost 2 nJ  pulse  energy.  In  contrast  to  SESAM-based laser,  the SWCNT  mode-locked  laser  generates 450-fs  pulses  of  mW-level  average  output power respectively.