基于下山单纯形算法逆向设计二维光子晶体波导型1×5分束器  

Two-dimensional photonic crystal waveguide 1×5 beam splitter reversely designed by downhill-simplex algorithm

作　　者：柯航 李培丽[1] 施伟华[1] Ke Hang Li;Pei-Li;Shi Wei-Hua(College of Electronic and Optical Engineering,Nanjing University of Posts and Telecommunications,Nanjing 210023,China)

机构地区：[1]南京邮电大学电子与光学工程学院,南京210023

出　　处：《物理学报》2022年第14期131-140,共10页Acta Physica Sinica

摘　　要：提出了一种新颖的二维光子晶体波导型1×5分束器,为了提高分束器的优化效率和分束性能,利用下山单纯形算法,对提出的1×5分束器进行逆向设计和研究.结果表明,改变耦合区域介质柱半径、Y分支波导中央的调控介质柱半径及其横向偏移量,可以调节分束器5个输出端口的输出光功率比例;利用下山单纯形算法,根据特定的分光比目标,对耦合区域介质柱半径、调控介质柱半径及其横向偏移量进行优化,可以逆向设计出总透过率达到99%以上、附加损耗小于0.044 dB以及响应时间小于1 ps的不同分光比的1×5分束器.此外,对逆向设计的1×5分束器进行了工艺误差分析,确定了各优化参量在实际加工中允许的误差范围,为器件的制作提供了理论参考.该1×5分束器分光比设计灵活,优化效率高,性能优良,尺寸小,在光子集成电路等领域中具有广泛的应用前景.Beam splitter, whose main function is to achieve the splitting, combining and routing of optical signals, is an important component of photonic integrated circuits, passive optical network and other fields. Compared with the conventional beam splitter, photonic crystal beam splitter, which has the virtues of smaller size and higher transmission efficiency, is very suitable for high-density and large-scale integration. The traditional control variable method often used in the optimal design of photonic crystal beam splitter is time-consuming and inefficient. When parameter variables are large, it is difficult for beam splitter to achieve the optimal splitting performance. In addition, it is hard to realize flexible design of beam splitting ratio when optimizing multi-channel photonic crystal beam splitter by this method. In this paper, a novel photonic crystal 1×5 beam splitter, in which two special Y-junction waveguides are introduced into a completely two-dimensional square lattice silicon, is proposed and optimally designed by using downhill-simplex algorithm. Firstly, to determine the optimization range of each variable, the influences of the radius of the dielectric rod in the coupling region and the radius and the lateral offset of the regulating dielectric rod in the center of the two Y-junction waveguides on the five output ports of the 1×5 beam splitter are explored respectively by the plane wave expansion method and finite difference time domain method. The results show that the optical energy coupled from the main waveguide Wto the upper Y-junction waveguide and lower Y-junction waveguide can be controlled by optimizing the radius of the dielectric rod in the coupling region. The transmittance of the five output ports can be controlled in proportion by optimizing the lateral offset of the regulating dielectric rods. The total transmittance of the five output ports can be improved, and the output of each port can be adjusted by optimizing the radius of the regulating dielectric rod. Then, according to

关 键 词：分束器 逆向设计 下山单纯形算法 光子晶体 

分 类 号：O734[理学—晶体学]