A sub-100 fs stretched-pulse 205 MHz repetition rate passively mode-locked Er-doped all-fiber laser

We present an all-fiber, stretched-pulse Er-doped fiber laser mode-locked by nonlinear polarization evolution with a novel resonator design, incorporating a hybrid component serving as a pump coupler, isolator and output coupler. The laser was capable of generating 93 fs laser pulses with a fundamental repetition frequency of 205 MHz and an average output power of more than 70 mW. The laser resonator consists of only three fiber-optic components, which makes the setup simple, compact and reliable. An integrated booster amplifier serves in this setup as a dechirping, amplifying and pulse duration tuning addition.