低功耗有机／无机混合结构热光开关的研制

Design and fabrication of an organic/inorganic hybrid thermo-optic switch with low power consumption

利用聚合物材料SU-8作为芯层、聚合物材料PMMA作为上包层和无机材料SiO2作为下包层,设计并研制了一种有机/无机混合结构的Mach-Zehnder干涉(MZI)热光(TO)开关。为了保证波导中的单模传输、减小模式辐射损耗和衬底泄露损耗、缩短响应时间并降低器件功耗,对其结构参数做了优化。利用化学气相沉积(CVD)、涂膜和湿法刻蚀等工艺制备了器件样品。在1 550nm工作波长下,器件的开和关状态的驱动功率分别为0和13mW(开关功率为13mW),开和关状态间的消光比为18.3dB。在方波驱动电压信号作用下,测得器件的上升和下降时间分别为126和134μs。与无机材料Si/SiO2和全聚合物材料研制的TO开关相比,本文研制的混合结构器件综合利用了芯层聚合物材料热光系数大、上/下缓冲层厚度均较小以及Si/SiO2导热系数大的优点,因此同时具备了较低的功耗和较快的响应时间,在光通信系统中具有较好的应用前景。

An organic/inorganic hybrid Mach-Zehnder interferometer （MZI） thermo-optic （TO） switch is designed and fabricated by using the negative photoresist SU-8, polymer PMMA and silica as core, upper cladding and lower cladding, respectively. The structural parameters are optimized for assuring fundamental mode propagation, decreasing radiation loss and leakage loss, shortening response time and minimizing power consumption. Fabrication techniques,including spin-coating and wet-etching, are adopted to develop the device sample. Under 1550 nm,the driving powers at ON state and OFF state are measured to be 0 and 13 mW,respectively,which indicates the switching power is 13 mW. The extinction ratio between ON state and OFF state is 18.3 dB,and under the square-wave switching signal,the rise time and fall time are 126 μs and 134 μs,respeetively. Compared with the thermo-optic switches with Si/SiO2 structure and full polymer structure, the proposed hybrid device possesses low power consumption and fast response simultaneously,owning to the advantages, including large TO coefficient for polymer core material, thin upper/under claddings and larger thermal conductivity of silica relative to polymer.