One-Dimensional Optical Beam Steering Based On A Silicon Photonic Phased Array

With the development of silicon integrated circuit chips in the past half-century,more and more attentions have been paid to the mature silicon fabrication technologies.Even the traditional light detection and ranging(LIDAR)technology has recently considered silicon photonics platform as an optimal choice.Owing to the advancement of autonomous vehicles and robotics,LIDAR systems have been promoted to a high level.However,most LIDAR systems today adopt the discrete free-space optical components and use a mechanical apparatus for beam steering.This implementation scheme intrinsically limits the beam scanning speed of LIDAR systems.Besides,the size,cost and complexity of such product are not competitive in the future market.This leads to a new implementation scheme of using silicon optical phased array(OPA)to solve the current issues.This thesis is focused on the design and realization of a large-steering-angle and high-scanning-speed silicon one-dimensional optical phased array(OPA).Firstly,far-field diffraction of the steered optical beam is theoretically analyzed.A theoretical model is built to simulate the far-field optical field patterns,and key parameters that influence the far-field patterns are analyzed.Secondly,the composite components,operation principles and functions in the OPA are introduced.Finally,experimental measurement is carried out to confirm the proper operation of the OPA chip.With a tunable input wavelength,the steering angle of the output beam covers the 30° range in the experimental system.The voltage on the phase shifters can also change the beam steering angle.The phase shifter is one of the most important components in the OPA.In order to improve the phase tuning accurancy,this thesis proposes a novel phase tuning structure based on a self-coupled optical waveguide.The coupled-mode theory(CMT)is used to analyze the amplitude and phase variation at the electromagnetically-induced-transparency(EIT)-like resonance frequency.Its feasibility to be used as the phase shifter in the OPA is analyzed.