Optimization for grating length of 980nm single-mode semiconductor laser with dual fiber Bragg grating

The analytical expression of transmittivity and reflectivity of dual fiber Bragg grating (FBG) and the gain equations of the laser are obtained by the coupled mode theory. The laser gain curve is studied through the length of dual FBG and optical fiber length between two gratings under coherence collapse. The relative parameters have been optimized to get the best mode-stabilizing characteristics. The output spectral characteristics and the output power of the laser with dual FBG are practically measured. At the temperature of 0°C~70°C, the wavelength shift is 0.5nm. The side mode suppression ratio (SMSR) is more than 45dB. The Full Width at Half Maximum (FWHM) is less than 1nm.