Generation of h–Shaped pulse in a mode–Locked erbium-doped fiber laser

In this paper, the generation of h-shaped pulse is demonstrated in a nonlinear polarization rotation mode-locked erbium-doped fiber laser (MLEDFL). The length entire cavity about 2506 m to enhance effect cavity. multi-pulse state obtained firstly under certain pump power and state. By further adjusting controller with sharp top flat bottom generated ∼100 mW. And duration tuned range 54.63–470 ns. width intensity trailing part vary differently during process increasing width. results indicate that peak clamping weak birefringence dominate different forming process.