Sampled Grating Distributed Bragg Reflector (SGDBR) light source is a current driven wavelength tunable light source. This paper introduces the principle characteristics of the light source, through the platform of automatic calibration system to establish the light source driving current and output light wavelength combination relationship, then the relationship between design for photoelectric system circuit board level, and spectral parameters of the light output are validated by experiment. A low cost scanning light source used in fiber Bragg grating demodulation instrument is obtained.