Design of distributed Bragg grating in 1064nm narrow linewidth DBR lasers

DBR lasers are attractive light sources due to their narrow linewidth, well stability frequency and large side-mode suppression. In the design, a 3 mm long active gain section and a 1 mm long passive 6th order surface Bragg grating consist of a 4 mm device. The wide of ridge waveguide is 3-4 μm. The rear facets (grating side) are not coated and the front facets are coated to a reflectivity of 30%. For reducing the difficulty of grating fabrication, we choose 6th order surface grating which period is a round 960nm. The effective reflection coefficient of DBR-section is approximately 55% Based on the ridge-waveguide structure, we use holographic lithography and dry etching to fabricate Bragg gating on ridge-waveguide.