Studies on characteristics of optical add/drop multiplexer using an asymmetric grating coupler

在本课题中，我们提出了一种用于光子网络光路由器的新型光加/丢复用器结构，并试图通过实验的方式研究所生产器件的光学特性。本课题研究成果总结如下：(1)所研究的光加/丢复用器具有折射率周期性变化的定向耦合器结构。在该设备中增加或减少特定波长的光功率。在这个项目中，我们提出了一种新的结构，并通过理论研究和数值计算阐明了其特点。(2)尝试通过实验的方式，提出了一种新的光学加/丢复用器结构，并对其进行了理论研究。试制方法是对光纤侧面进行抛光处理。我们现在还在继续，并没有完成研究。然而，我们找到了抛光的条件，通过这种条件，我们可以得到均匀的抛光面和复制。结果表明：在非对称光栅耦合器中，偶模与奇模之间的耦合效率为1.100%。对称型光栅耦合器在特定参数下的反射效率达到90%以上，这方面的研究尚未见报道。提出的新型光耦合器有望实现小尺寸光复用器。光纤的抛光面难以精确控制。通过实验的方式生产光纤光栅耦合器还需要进行更多的研究。

In the project, we proposed a new structure of optical add/drop multiplexer for use of optical routers in photonic networks and tried to study the optical characteristics of devices produced by way of experiment. Summary of research results, which we studied in this project, is as follows :(1)Optical add/drop multiplexer, which we studied, has a directional coupler structure with periodic refractive index changes. Optical power with a specific wavelength is added or dropped in this device. In this project, we proposed a new structure, and clarified the characteristics by both theoretical investigations and numerical calculations.(2)We tried to produce the new structure of optical add/drop multiplexer, which we theoretically studied, by way of experiment. Method for trial production is polishing of the side faces of optical grating fibers. We are now going on, and did not finish the studies. However, we found conditions for polishing, by which we can get uniform polishing side faces with reproduction.Detailed results are as follows :1.100% coupling efficiency is obtained between even mode and odd mode in the asymmetric grating coupler.2.More than 90% refection efficiency is obtained for specific parameters in symmetric grating coupler, which has not yet been reported.3.The new optical coupler proposed is hopeful for realization of small size optical multiplexers.4.It is difficult to control polishing faces precisely in optical fibers. More studies, are needed to produce the optical fiber grating coupler by way of experiment.