Abstract:We present a novel and efficient L-band wavelength-tunable Er3+ doped fiber laser of ring structure. In the cavity two segments of Er3+ doped fiber and a fiber Bragg grating are used to improve pump efficiency. Tunable filters based on fiber loop mirrors are also applied inside the cavity to act as both a wavelength selector and a line-width compressor. Using these techniques, a tunable laser with tuning range up to 42 nm, output power larger than 1 mW, power uniformity controlled within 1.75 dB and side mode suppression ratio about 40 dB is achieved. This project (2005-28) is supported by Laboratory of Opto-electronics Information Technical Science, EMC.