In this paper, we report the experimental study of erbium-doped mode-locked fiber laser using semiconductor saturable absorber mirror (SESAM). Two configuration erbium-doped mode-locked fiber lasers, single wavelength operation and multi-wavelength operation, are study systematically. In single wavelength operating configuration, the fiber laser can operate harmonic mode-locking of 31 MHz repetition rate, which is two times of the fundamental repetition rate in our setup. In multi-wavelength operation, the output spectrum range from 1550 nm to 1556 nm with interval of 0.8 nm. The self-starting passive mode-locked laser is constructed in a Fabry-Perot configuration using the saturable absorber mirror as the back reflector of the cavity. Fiber Bragg grating and Chirped Bragg grating are used as the other reflector. Both of our mode-locked lasers are very compact, the output pulse train is stable, which has potential applications in high speed optical communication and optical sensor.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.