Scanning Performance Analysis And Optimization Of Waveguide Optical Phased Array

Waveguide optical phased arrays have many significant advantages, which can overcome the lack of traditional phased array technology, such as their high resolution, scanning speed, low driving voltage, low cost and so on. They can be used in laser radars, scanning, guidance, imaging, and recognized with a bright future. However, the limitations of production process and design flaws result in correspondingly lower quality of the radiation field scanning optical beam and unable to improve the diffraction efficiency and scanning accuracy. Therefore, the optimization approach of scanning beam quality has an important theoretical and practical significance for the further development of the waveguide optical phased array technology.In this paper, the working principle and the structure of waveguide optical phased array are introduced in detail. Considering the optical waveguide coupling effect based on the model of diffraction grating, the effect of the far-field output on coupling effect is discussed based on the coupled-mode theory. We analyze the influences of different physical parameters on the beam scanning characteristics of waveguide optical phased array. Then we obtain that the number of units N can affect the resolution of scanning beam and the extinction coefficient K can affect the power of scanning beam.Because of the limitation of microelectronic technology, the method of combining several arrays is proposed to increase the waveguide unit number N. The theoretical analysis and simulation of different combination ways are given. The experimental data is obtained and the feasibility of the approach is verified. An optimization method of uneven spacing distributions is presented, and can improve the problem of scanning beam streaks produced by arrays combination.The optical power leakage from the substrate with high refractive index will decrease the output efficiency and the optical power. So the method of increasing the isolation layer is proposed to destroy the high refractive index substrate environment. It can reduce the optical power loss and improve the optical performance of scanning beam in theory.