The purpose of this thesis is to design and fabricate the S-shaped profile in depth. The results are applied to design a beam expander. In the experiments, we use the local etch-rate control, i.e. diffusion-limited etching, to fabricate the S-shaped profile. The etchant solution and recipe is H3PO4:H2O2:H2O =98:1:1 at 21¢J without stirring. The diffusion length of the etchant solution is 12.5mm. The device includes active semiconductor laser and passive tapered waveguide (beam expander). The design of the passive waveguide includes the lateral and vertical directions. In the lateral aspect, we use FimmWave to simulate the best symmetrical far field angle. When the waveguide width is 2.5mm and the etching depth is 1.4mm, we can get the best symmetrical far field angle which is lateral 27.88¢X and vertical 27.76¢X. In the vertical aspect, we use diffusion-limited etching to fabricate the depth changing. In this thesis, we use the beam expander length 350, 400, 450, 500mm.