Design And Fabrication Research Of Waveguide-type RGB Beam Combiner

With the rapid development of display technology,people have higher and higher requirements for visual experience.Virtual reality,augmented reality and hybrid reality technology are an important way for human beings to obtain visual information.As an application of these technologies,people put forward higher requirements for its performance.The planar optical waveguide RGB beam combiner plays a core role in the laser image projection system and plays an important role in promoting its miniaturization and high performance.RGB beam combiner is manufactured by planar optical waveguide loop process.It has the advantages of compact structure,high performance and low cost.It is an important part of the optical engine in miniaturized laser image projection.In recent years,it has become a research hotspot in the field of projection.In this paper,the theoretical analysis,modeling and simulation design,manufacturing and testing of planar optical waveguide RGB beam combiner are studied.The main research contents of this paper are as follows:(1)The planar optical waveguide RGB beam combiner and its research status are introduced;The basic theory and analysis methods of planar optical waveguide are introduced,including effective refractive index method and beam propagation method;The working principle and design method of RGB beam combiner are introduced;The coupling theory of optical waveguide is introduced;The theory of parameter sensitivity analysis and Morris screening method are introduced.(2)Based on the optical waveguide theory and beam propagation method,the RGB optical combiner is modeled and simulated,and the relationship between structural parameters and optical performance of four kinds of planar optical waveguide RGB optical combiners with relative refractive index difference of 0.5%,0.75%,1% and 1.5% is analyzed and studied;Based on the results of optimization design,the process tolerance is analyzed;Based on the parameter sensitivity analysis theory,the sensitivity analysis results of each RGB beam combiner are obtained,and the influence of structural parameters on optical performance is analyzed;Under the conditions of four different refractive index differences,the planar optical waveguide RGB beam combiner with average output efficiency of 93.4%,90.8%,94.8% and 95.5% is optimized in turn,and its structural dimensions are 60μm×6540μm,60μm×6540μm,60μm×4100μm,60μm×3550μm.(3)The main manufacturing process and key technology of planar optical waveguide loop technology are introduced.A planar optical waveguide RGB optical combiner with relative refractive index difference of 0.75% is designed and fabricated by using planar optical waveguide loop technology.The optical performance test platform of RGB optical combiner is built.The manufactured RGB optical combiner is tested experimentally,and the experimental results are compared with the simulation results.The average output efficiency of RGB beam combiner simulation results is 90.8%,and the maximum output efficiency of RGB optical combiner is 71.3%,which is lower than the simulation results.The reasons for the gap are analyzed,and the feasibility of manufacturing planar optical waveguide RGB optical combiner is verified.