Study Of The Silicon-based Optical Phased Array

In rencent years,intelligent systems attract almost all the world's attention.All kinds of unmanned systems are quietly changing the world and people's lives.Advanced ability of environmental awareness becomes a quite necessary condition for the realization of an.unmanned system.Relevant sensor technologies have become the core link in the key technical system that supports the development of an intelligent unmanned system.Lidar,as an important sensing technique,is largely limited in its operation way of mechanical scanning at present,and is suffering from its large size and slow scanning speed.Taking advantage of silicon-based photonic integration technology,designing and manufacturing a beam steering device with small size and fast beam scanning speed has much important significance.The silicon-based optical phased array(OPA)consists of a set of arrayed light output cells whose phases can be controled to achieve far-field radiation beam steering.Based on the fully theoretical study and the experience of predecessors' design,this dissertation fully studies the silicon-based phased array and takes the actual situation of our research group into consideration,designs and constructs the Fourier imaging system,which is used as the far-field map system of the silicon-based optical phased array.We designed and manufactured many OPA elements,from easy ones to complicated ones.The Fourier imaging system is used to test and characterize the far-field pattern of our chips.We also set up a silicon-based optical phased array feedback optimization system,which is used to optimize the radiation pattern of the corresponding devices.The optimization results verify the feasibility of the feedback optimization system.The main contents of this article are as follows:1.The basic theory of silicon-based optical phased array is introduced.The complete theoretical analysis is given from the calculation of the far-field radiation pattern of a single radiating element to the calculation of the far-field radiation of the array radiating elements.The main structure of silicon-based optical phased array is introduced.Taking the actual elements we designed as an example,the characteristic parameters of the key devices(MMI(Multimode interference)splitter,output grating array and heaters group)are simulated and analyzed.2.Far-field test system of silicon-based optical phased array is set up.Taking the static test and characterition of one-dimensional silicon-based optical phased array as an example,the testing procedure of far-field radiation results is introduced in detail.The radiation characteristic of one-dimensional phased array is tested and analyzed.3.We design and build a silicon-based optical phased array feedback optimization system,which is used to optimize the phased array to enhance the far-field radiation results.We design and manufacture an 1× 8 closely arranged optical phased array device.The feedback optimization system is used to improve the extinction ratio of the mainlobe to the sidelobe in the far-field radiation result.4.We design and manufacture an un-uniform optical phased array device to minimize the sidelobes.Using the feedback optimization system,we characterize its radiation pattern and verify its function.