中文摘要：

为改进传统Y分支光分路器损耗较大的缺陷,我们采用激模波导结构设计新型Y分支波导和由三个分支级联的新型Y分支波导构成低损耗1×4光分路器。设计中利用辐射模和本征基模的叠加来修正光波场,通过改善模匹配来降低分支耦合损耗,同时在1×4光分路器中加入直波导来改善和优化分路器的输出均匀性,并用有限差分光束传播法对该Y分支波导和1×4光分路器进行数值模拟。模拟结果表明,该结构具有均匀性好、损耗小和结构简单等优点,有利于器件的进一步集成和大批量生产。

英文摘要：

In Order to improve the relatively great loss of Y branch optical splitter, a new designed Y branch of transitional wavegnide structure and a new low-loss 1×4 optical splitter of three cascaded branches are adopted. In the design, radiation mode and fundamental mode are overlapped to modify the mode field. The improved mode matching is used to reduce the branching loss. Meanwhile, add a straight waveguide in the 1×4 optical splitter to reform and optimize the symmetry of output of splitter. The functions of Y branch optical waveguide and 1×4 Optical splitter are simulated by Finite-difference Beam Propagation Method （FD-BPM）. The results indicate that this structure has the advantages of good homogeneity, low loss, and simple structure, and is propitious to further integration and production in batches.