Si基槽型光波导的传输特性分析和传输损耗的测量

对Si基槽型(slot)光波导的传输特性进行了研究。 采用三 维时域有限差分(3D-FDTD)法研究了芯层中的光功率与波导槽型宽度及Si条带宽度之间的关 系,结果显示,槽型光波导具有很好的光功率约束效率,可以达到30%以上; 分析了光功率的变化规律及其优化,综合考虑光功率和光功率密度确定波导结构参数,实现 最佳光功率分 布,横向光功率分布沿x轴方向具有很好的约束效果,沿y轴方向呈现高斯分布；分析了底部Si薄层对光 功率的影响,100nm的底部Si薄层使得芯层的光功率下降50%,减小 底部Si薄层厚度有利于光功率约束效 率的提高;采用电子束刻写(EBL)技术和等离子刻蚀(ICP)技术制备了Si基槽型光波导,实验 研究了其传输损耗,结果显示,槽型光波导具有较低的传输损耗,达到13.5dB/cm。

Researches on the transmission properties of the silicon slot optical waveguides and the transmission loss measurement

The transmission properties of the sil icon slot optical waveguides are researched.The relationships between the slot o ptical power and the widths of the slot and silicon strip are studied by using F DTD method. Results show that silicon slot optical waveguides can offer good power confineme nt efficiency which can be as high as 30%.The optical power confinement and its optimization are analyzed.The waveguide parameters of the slots can be optimized by taking the optical power and power densit y into account,by which a best field distribution can be obtained.The field distribution at the cross section shows an excellent confinement along x direction and a Gaussian distribution along y direction. The effects of the t hin silicon bottom slab on the power confinement are studied.A 100nm thick silicon bottom slab will decrease the po wer in the slot by 50%.A slot waveguide is fabricated on SOI wafer by using electron beam lithography and plasma etching technologies.The transmission loss is studi ed experimentally.Results show that it has a good transmission loss as low as 13.5dB/cm.