2D-3D异质结结构中超短耦合长度的研究

采用时域有限差分法分析、模拟和设计了2D-3D异质结结构中的定向耦合器,并且通过非平面和平面的优化设计实现了小于2a（a为晶格常数）的超短耦合长度。研究结果表明,当位于耦合区域的晶格常数由1.25a-1.25a-1.25a-1.25a变为1.5a-2.0a-1.5a时,获得的耦合长度小于3a;同时将位于输入波导和耦合波导之间介质柱的宽度减小到0.18a,可获得小于2a的超短耦合长度。该耦合长度对于实现密度集成电路的小型化非常重要。

Investigation of ultra-short coupling lengths in 2D-3D hetero-structures

A directional coupler in 2D-3D hetero-structures is analyzed, simulated, and designed in detail using the finite difference time domain method. By both plane and off-plane adjustment, ultra-short coupling lengths less than 2a can be realized. The results show that coupling lengths less than 3a can be obtained when the lattice constant located at the coupling region is increased to 1.5a-2.0a-1.5a, where a is the lattice constant. Furthermore, when the rod width, which is located between the input and output waveguides, is reduced simultaneously to 0.18a, an ultra-short coupling length less than 2a is also obtained. This characteristic is very important in the design of compact integrated circuits.