Numerical Study of Grating Coupler for Beam Steering

Emerging integrated photonic that studies the generation, processing, and detection of light in chip-scale optical media is one of the most important topics in modern optics research. Grating couplers have raised tremendous research interest due to its outstanding performance in compact non-mechanical beam steering, especially its potential applications in Solid State Lidar. In this work, the mechanism of one beam free-space coupling is introduced, the effects of different parameters in the grating coupler design, such as period size, number of total periods and etching depth are simulated and analyzed by FDTD method. And base on the numerical study of one beam grating coupler, we proposed a novel design of a compound period grating coupler formed by combining two grating structures with different periodicities. The new compound period grating coupler structure can couple the waveguide mode into two radiation modes with different angles. Therefore, the beam steering range is doubled due to the extra beam. We numerically demonstrate this idea, and a 26.20° steering range is observed within a wavelength tuning range of 1500 nm to 1600 nm. In addition, the investigation of fabrication tolerance shows that the new structure can be fabricated with the current CMOS technology.Master of Science in Engineering (MSE)Automotive Systems Engineering, College of Engineering & Computer ScienceUniversity of Michigan-Dearbornhttps://deepblue.lib.umich.edu/bitstream/2027.42/146795/1/Master Thesis_Wei Guo.pdfDescription of Master Thesis_Wei Guo.pdf : Thesi