Distributed feedback semiconductor laser based on reconstruction-equivalent-chirp technology and the manufacture method of the same

Abstract

Using sampled Bragg grating structure, the present invention proposes a distributed feedback (DFB) semiconductor laser based on reconstruction-equivalent-chirp technology. Namely, the Bragg grating in the said DFB semiconductor laser cavity is a sampled Bragg grating, in which there is an equivalent grating corresponding to the original ordinary DFB grating as feedback for lasing. The laser wavelength of the said semiconductor laser located within the operation bandwidth of the said equivalent grating. The said equivalent grating is designed and fabricated using REC technology and has equivalent chirps, one equivalent phase shift or multiple equivalent phase shifts. The said sampled Bragg grating has multiple ghost gratings and the wavelength spacing between neighboring ghost gratings is inversely proportional to the sampling period and the effective refractive index of the said semiconductor laser. Only one ghost grating except the ghost grating related to the center wavelength is selected to be as equivalent grating. In semiconductor laser fields, only based on sub-micron precision, the present invention provides a method to realize various complex equivalent chirps and equivalent phase shifts in the resonant cavity of the said semiconductor laser. These equivalent chirps and equivalent phase shifts have the same functions with the corresponding true chirps and true phase shifts, so as to avoid the processes of fabrication of grating structure with complex true chirps and true phase shifts.