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随着全光通信的快速发展,波分复用传输系统已不能满足高容量光网络的需求,而模分复用技术利用有限的稳定模式作为独立信道传递信息,可以成倍地提高系统容量和频谱效率,是构建未来光网络的关键技术之一.本文基于掺Bi复合稀土铁石榴石的磁光效应,设计了1.55μm波段的二维三角晶格光子晶体模分复用器.在该光子晶体结构中引入缺陷,形成模式分束波导,通过外加磁场改变其在不同偏振模式下的磁导率,从而控制TE,TM模式的传输,实现了1.55μm波段的模分复用.利用平面波展开法和时域有限差分法对此模分复用器进行了能带和传输特性分析,结果表明:TE和TM模式的透射率均高于92%,信道隔离度分别为19.7 dB和42.1 dB.这些特性在未来的大容量光传输系统中有着重要的应用前景.
With the rapid development of all-optical communications, WDM systems can no longer meet the needs of high-capacity optical networks. However, the use of a limited number of stable modes as a separate channel for the transmission of information can improve the system capacity and Spectral efficiency is one of the key technologies to build the future optical network.In this paper, based on the magneto-optical effect of Bi-doped rare earth iron garnet, a two-dimensional triangular lattice photonic crystal multiplexer with a wavelength of 1.55μm was designed. In the crystal structure, a defect is introduced to form a mode-splitter waveguide, and the permeability in different polarization modes is changed by the applied magnetic field to control the transmission of the TE and TM modes, thereby realizing the mode-division multiplexing in the 1.55μm band. The results show that the TE and TM modes transmit more than 92% and the channel isolation are 19.7 dB and 42.1 dB, respectively. These characteristics have important application prospects in the future large-capacity optical transmission system.