A special sampling structure based on the double exposure technology is proposed to achieve dual-wavelength lasing in the distributed feedback (DFB) fiber laser. This structure is composed of two grating pitches in one sampling period, which could be realized by changing the fiber's length in the fabrication. And through employing an equivalent phase shift, only a submicrometer-level precision is required for precise phase control. Then a stable dual-wavelength laser with the spacing of 400pm is obtained in the experiment successfully. The output power is 30.46uW and the SMSR is 46dB under a pumped power of 146mw.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.