Oscillation wavelength of fiber Bragg grating semiconductor lasers

Based on the physical fact that a laser containing a gain medium with homogenous line broadening oscillates at the wavelength which requires the smallest threshold gain due to the mode competition effect, after taking into account the wavelength-depended reflectivity distribution profile of a fiber Bragg grating, the oscillation wavelength λ_l of fiber Bragg grating semiconductor lasers has been investigated theoretically. The results show that the laser oscillation wavelength λ_B is not fixed at the Bragg reflection wavelength λ_l of fiber Bragg grating, and the offset between λ_B and λ_l depends on the reflectivity distribution profile of fiber Bragg grating and the gain profile of semiconductor gain medium.