基于偏振双折射棱镜的光学相控阵角度放大级研究

Study of optical phased array angular magnification based on polarized birefringent prism

为了扩展光学相控阵的角度扫描范围,研究了偏振双折射棱镜结构对角度放大性能的影响,分析了限制放大倍数和光束偏转效率的主要因素,并提出了相应的优化设计方法。研究结果表明:放大级中各级双折射棱镜的结构角和入射光角度决定了出射光角度分布,要获得更大的角度范围和均匀的角度间隔,应优化设计各级双折射棱镜的结构角;要提升放大倍数,应设计更大的结构角或者增加级联双折射棱镜数量,但这些都受到光束走离效应的限制,实际中应结合相控阵要求的通光口径和最小角度间隔等因素进行综合设计;放大级系统中,偏振控制误差是造成杂散光的主要因素,应严格控制各级液晶波片的驱动电压。

To extend the angular sweep range of optical phased array （OPA）,the influence of the polarized birefringent prism （BFP） group′s structure on the performance of angular-contr olled ability is studied. Some main factors which limit the magnification and deviation efficiency are analyzed,and corresponding optimization methods are proposed.The results show that the di stribution of output beam directions is determined by the BFP group′s wedge an gle and incident angle,so BFPs′ wedge angles should be optimized to get wider sweep range and more propor tioned distribution.To obtain higher magnification,BFPs with bigger wedge angles shou ld be chosen,and more BFPs should be adopted,but these will be limited by the beam walk -off effect,so it is necessary to consider the requirements of minimum angle interval and caliber in the OPA application to make an integrated design.In the magnification system,the error in the manipulation of polarization is the main factor of stray light,so the driving voltage of liquid crystal wave plates should be strictly controlled.