Finishing of Rough Sidewalls of a Silicon-on-Insulator Nano-Optical Waveguide Using Laser Surface Melting

The 2D numerical model for finishing rough sidewalls of a silicon-on-insulator nano-optical waveguide using laser surface melting is built based on the heat transfer theory. The effect of two important parameters, incident angle and mean energy density of the laser beam, on the temperature field and shape of the weld pool is discussed. The process parameters are optimized. Based on the literature data and the requirements to the weld pool shape in the finishing of rough waveguide sidewalls, its shape is proposed to be optimized after determining the incident angle of the laser beam. Then, an appropriate mean energy density is selected to obtain a sufficient melt depth. In melting, the incident angle should be equal to or exceed 60°, and a larger incident angle is preferred for smoothing the rough sidewalls. For the application of waveguides in optical integrated circuits, the incident angle of the laser beam is proposed to be first determined, and then an appropriate mean energy density to be chosen for finishing their rough sidewalls.