Stable Nanosecond Chirp-free Pulse Generation with Ultra-narrow Bandwidth from a Passively CW Mode-locked Fiber Laser

A stable nanosecond chirp-free pulse generation with ultra-narrow bandwidth is established from a passively mode-locked erbium-doped fiber laser with a homemade fiber Bragg Grating as the intra-cavity filter and careful intra-cavity dispersion management introduced.