Patent ID: 7012944

Claim:
A single-wavelength distributed feedback (DFB) laser structure having two sections, comprising: an active-material layer for generating a laser light having a wavelength in a specific range; two cladding layers respectively covering an upper and a bottom sides of said active-material layer for forming a waveguide structure; a phase shift layer having a specific thickness for controlling a difference between Bragg wavelengths of said two sections; a grating layer having a specific period for determining an illuminating wavelength; a wet-etching stop layer positioned between said active-material layer and said grating layer, wherein said wet-etching stop layer and said grating layer cooperate with each other for controlling a coupling index of said grating layer; and another wet-etching stop layer positioned between said phase shift layer and said grating layer, wherein a difference between said two sections is an existence of said phase shift layer thereon, and said existence of said phase shift layer causes a difference of the effective refractive indices between said two sections so as to generate a fixed difference between Bragg wavelengths of said two sections.