提出并研究了一种带隔热槽的马赫曾德尔干涉结构聚合物波导可调耦合器。仿真分析了热光电极作用下有、无隔热槽的耦合器波导温度分布，表明设置隔热槽可以降低热光调谐所需的功耗。研究了铝电极作用下不同上包层厚度对光传输损耗的影响，确定了上包层厚度。根据隔热槽与电极之间距离对热光调谐功耗的影响，结合隔热槽对导波光模式的影响及波导制备工艺，确定了隔热槽的位置。最终设计的带隔热槽聚合物波导可调耦合器实现1~0的分束比所需功耗为2.20 mW，是无隔热槽的47.4%。

A tunable polymer waveguide coupler based on Mach-Zehnder interferometer (MZI) with thermal isolation trenches (TITs) is proposed and analyzed. The temperature distribution in the cross section of polymer waveguides with and without TITs is simulated, which illustrates that the TITs can reduce the power consumption efficiently. The proper thickness of up-cladding waveguide is chosen through investigating the propagation loss of guided modes under aluminium electrode. According to the power consumption influenced by the distance between the TIT and the metal electrode, the optical loss induced by the mode mismatch of the waveguides with and without TITs, and precision of the fabrication craft, the position of TITs is determined. To realize the splitting ratio from 1 to 0, the power of the designed tunable polymer waveguide coupler with TITs is 2.20 mW, which is only 47.4% of the coupler′s power without TITs.