集成式二维相控激光扫描芯片的研究

Beam steering technology has wide application prospect in both military and civilian fields. Aiming at the bottleneck issues about miniaturizing and integrating of the beam-steering device and facing international technology development trend , this project proposes methods and techniques for integrating laser source with optical phased array in order to realize integrated phased beam-steering chips. Large-scale vertical cavity surface emitting laser (VCSEL) phase locked arrays are designed and developed for a large-area uniform coherent laser source. Then the transmission optical phased array is designed and integrated on the surface of the VCSEL phase locked array by using conventional process. The elements between the optical phased array and the VCSEL phase locked array couple directly and efficiently with each other with no need for any other optical system. The VCSEL array and the optical phased array which steers laser beam are electrically controlled independently. The project takes the integration between liquid crystal optical phased array and implantation-defined VCSEL phase-locked array as the typical research object. The single-mode operation, the in-phase locked mechanism and the polarization stability of large-scale VCSEL phase-locked arrays are studied. Analysis of the coupling mechanism between the optical phased array and the VCSEL phase-locked array are carried out. Integrated theoretical model and structure design of the chip are developed. The key scientific and technical problems of the integrated chip, such as numerical analysis, structure design, preparation process, integration technology and testing technology are studied to realize the small and reliable beam-steering device. Considering the low-cost of the liquid crystal optical phased array and the implantation-defined VCSEL phase locked array, this integrated phased beam steering chip has a good practical application prospect in the future.

光束扫描技术在军事民用领域有广泛应用前景。针对光束扫描装置微型化的国际发展趋势和技术瓶颈，本项目提出将激光源和光学相控阵片上集成的方法和技术，研制集成式二维相控激光扫描芯片。设计研制大规模垂直腔面发射激光（VCSEL）锁相阵列作为大面积均匀相干激光源，在其表平面上采用常规工艺集成透射式光学相控阵，二者的各单元一一对应，无需光学系统，耦合效率高，结构简单。相控阵调节激光束偏转，与激光源分别独立控制。项目以透射式液晶光学相控阵和质子注入型VCSEL锁相阵列的集成为主要研究对象。研究大规模VCSEL阵列的单模同相锁相机制和偏振稳定性；分析相控阵与锁相阵列耦合的机制，研究集成芯片的一体化理论模型和结构设计；研究相控阵和锁相阵列的制备工艺和集成技术，以及集成芯片的测试技术等关键科学和技术问题。实现微型相控光束二维扫描技术。液晶及其相控阵技术和质子注入技术成本相对较低，利于该集成芯片实用和推广。

光束扫描技术是指对激光光束方向进行精准操控的技术，在军事和民用领域均具有广泛的应用前景。目前的大部分光束扫描装置结构复杂、体积庞大，光源与相控阵结构分离导致耦合效率低，可靠性差，难以满足现代光电系统微型化的趋势。. 本项目研究集成式二维相控激光扫描芯片及其偏转技术。将液晶光学相控阵与质子注入VCSEL锁相阵列集成，前者作为大面积均匀激光光源，后者作为光学相控阵调控光束偏转，二者独立控制。以透射式液晶相控阵和质子注入VCSEL锁相阵列的集成为研究切入点，研究大规模VCSEL 阵列的单模同相锁相机制和偏振稳定性；分析相控阵和锁相阵列的相互耦合机制，建立一套自洽的芯片一体化的理论分析模型；探究芯片结构与光束扫描角度之间的关系，并最终确定芯片结构；研究相控阵和锁相阵列的制备工艺和集成技术，以及芯片测试技术等关键科学和技术问题。通过测试分析，与模拟结果对比，改进模型和结构设计，优化工艺，实现优异的光束扫描特性。. 通过4年的研究工作，项目组掌握了大规模、单模和偏振稳定VCSEL 锁相阵列的耦合机理和结构设计，建立了一套自洽的光学相控阵和锁相阵列一体化的理论分析模型。通过数值模拟VCSEL 锁相阵列结构（如四方、六角结构）、规模，得到相关参数并设计相控激光扫描芯片结构。采用质子注入工艺，制备了发散角只有1°的19单元六角排列同相耦合阵列以及127单元超大规模六角同相耦合阵列。掌握了VCSEL 锁相阵列与光学相控阵的关键制备工艺和集成技术。采用常规半导体工艺，成功研制出VCSEL 锁相阵列与透射式光学相控阵片上集成的相控激光扫描芯片，实现光束一维扫描, 最大扫描角度可达6.06°。设计制备了基于微流控锁相VCSEL阵列的一维光束扫描传感芯片。设计了二维扫描芯片的结构模型，并对其远场模式和扫描角度进行了仿真计算。除此之外，我们采用在背出射VCSEL阵列出光端面集成超构表面的方案，实现了大角度的二维光束扫描。这些研究成果在光通信、激光照明、激光打印以及激光雷达等军事以及民用领域有着巨大的应用前景。