slot波导包覆层对功率密度的影响

Impact of Top Cladding on Power Intensity of Slot Waveguides

理论模拟研究了硅基绝缘(SOI)的slot波导中槽内限制功率与slot波导的结构参数以及包覆层折射率的关系。结果表明,如果包覆层的折射率偏离衬底SiO2的折射率,相同参数下的slot波导的传输损耗大于包覆层为SiO2的结构的传输损耗。分析表明,如果包层与衬底折射率不同,限制的光功率会从slot缝隙中渗透到折射率较高的衬底或者包层中,从而引起能量的损耗。理论模拟得到了在缝隙宽度为0.12μm的情况下,slot波导槽内最大的光功率限制为28.54%,这个值包含了纳米线波导与slot波导直接耦合产生的耦合损耗以及slot波导自身的传输损耗。

For slot waveguide based on SOI,the relationship between its structural parameters and the refractive index of the top cladding is theoretically studied.The results show that,if the refractive index of the top cladding is different from that of the substrate SiO2,the transmission loss in the slot waveguide will be higher than that of the waveguide with the same parameters.Tests indicate that the index difference between the cladding and the substrate will cause the confined power to infiltrate into the substrate or the cladding with a higher refractive index,which makes a big power loss.Simulation results show that the maximum optical power confinement Psof 28.5%is obained when the width of the slot Wsis 0.12μm.Such Psvalue contains the transmission loss of the slot waveguides and the coupling loss between the slot waveguide and the strip waveguide.