Bismuth-doped fiber Q-switcher in erbium-doped fiber laser cavity

We propose a simple design of all-fiber Q-switched erbium-doped fiber laser (EDFL). The laser is passively Q-switched by splicing bismuth-doped fiber into a ring cavity. The design has been experimentally demonstrated at the emission wavelength of 1560.48 nm. A single-mode Q-switched pulse with pulse duration of 1.18 mu s and pulse energy of 15.6 nJ was obtained with 980 nm pump power of 178 mW. Stable and typical Q-switched pulses were achieved at the repetition rate changing from 63.3 to 94.6 kHz. To the best of our knowledge, it is the first time to demonstrate bismuth-doped fiber as an effective saturable absorber for erbium-doped fiber laser.