Design And Test Of Silicon-based Optical Phased Array Chip

After entering the information society,the speed of technological development has increased tremendously.In particular,smart technology has made great progress in recent years.Intelligent software that relies on cloud computing and big data has been widely used.However,the related technologies of intelligent hardware still need to be further broken.The most important one is the 3D sensing technology.Currently,LIDAR always uses mechanical rotation to scan.Due to the mechanical structure,the LIDAR is large and the scanning speed is slow.Using phased array technology can avoid the mechanical structure,and thanks to the development of silicon photonic integration technology,the on-chip optical phased array can be manufactured.Based on the on-chip optical phased array technology,a miniature high-speed scanning LIDAR can be realized.This has an important role in promoting 3D sensing technology.Phased array technology is a beam scanning technique.It takes advantage of the interference effects of waves.Beam scanning can be achieved by changing the phase of each beam transmitting unit rather than mechanical motion.This makes it possible to implement a programmable random scan function.And phased array devices can achieve higher speed scanning.The phased array technology is appeared in the microwave band,and later it is expanded to the optical band.The chip-level device was manufactured with the help of integrated optical technology.However,since the wavelength of the electromagnetic wave in the optical band is much smaller than microwave band,the on-chip optical phased array technology has encountered many new problems which need to be solved.This paper focuses on the grating lobe suppression and chip test problem in optical phased array.The main contents of the thesis include:1.The theoretical introduction of phased array technology.Based on the superposition calculation of electromagnetic wave complex electric field,the formation principle of one-dimensional and two-dimensional phased array beams is discussed,and the causes of grating lobes are analyzed.The structure and performance characteristics of various optical phased arrays are summarized.In particular,the key optical components in silicon optical phased arrays are analyzed and compared.2.The design process of optical phased array is briefly explained.The grating lobe problem is analyzed in depth.Based on the conditions of grating lobes and the theory of grating lobes suppression,a method of grating lobe suppression is proposed.The method is based on random and circular antenna array,its effectiveness of the method is verified by simulation.3.The testing requirements of optical phased array chips is researched and analyzed in depth.A test proposal is proposed,including coupling,packaging,calibrating,near-field and far-field observing.Test platform has been built.And a few optical phased array chips are packaged,calibrated and characterized on the platform.4.The initial phase calibration problem is analyzed.Referring to the calibration method of microwave phased array,a modified routing elements electronical vector method is proposed.The stability and accuracy of the calibration method are verified by simulation and experiment.