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

在该项目中，我们提出了一种用于光网络中的光路由器的光分插复用器的新结构，并尝试通过实验的方式来研究所产生的器件的光学特性。本课题的研究成果总结如下：(1)我们所研究的光分插复用器具有周期性折射率变化的定向耦合器结构。在该设备中添加或丢弃特定波长的光功率。在本课题中，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它的特性。(2)通过实验的方式，我们尝试产生了我们从理论上研究的光分插复用器的新结构。试制方法是对光纤的侧面进行抛光。我们现在正在进行，并没有完成研究。结果表明：在非对称光栅耦合器中，偶模和奇模之间的耦合效率达到1.100%；2.对称光栅耦合器在特定参数下获得了90%以上的反射效率，这一结果尚未见报道；3.所提出的新型光耦合器有望实现小尺寸的光倍增；4.光纤中的抛光面难以精确控制。光纤光栅耦合器的研制还需要进一步的实验研究。

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.