Experimental Noise Characterization of a Mid-infrared Mode-locked Er:ZBLAN Fiber Laser

Mid-infrared laser sources have attracted significant attention in applications, such as spectroscopy, laser surgery, material processing and supercontinuum generation [1]. Many practical applications require low-noise and high-stability ultrashort pulses in mid-infrared region, and rare-earth (RE) doped fluoride fibers can provide the platform for generating such ultrashort pulses. Since the first demonstration of a mode-locked (ML) erbium-doped fluoride fiber laser operating at 2.7 μm [2], there has been many reports presenting the output power, pulse energy and pulse duration of ML RE-doped fluoride fiber lasers. However, the laser stability has so far only been evaluated by fluctuations in output power [3], while for many applications it is the pulse-to-pulse relative intensity noise (RIN) that is the limiting factor. In this work, we report the first experimental RIN characterization of a ML erbium-doped ZBLAN fiber laser.