基于狭缝波导结构, 设计了工作波长在890 nm的聚合物基微环。从折射率传感的角度详细分析了狭缝波导的模场特性。分析了波导高度、宽度及狭缝宽度对灵敏度的影响。传统的狭缝波导具有较高的弯曲损耗, 这会影响微环谐振器的品质因子Q以及消光比。设计了非对称的狭缝结构, 保证波导模式位于波导中央传输, 降低弯曲损耗。为了条形波导与狭缝波导更好的耦合, 设计了基于多模干涉结构的条形-狭缝波导模式转换器。仿真表明设计的微环谐振器的传感灵敏度达到109 nm/RIU。

Based on slot waveguide structures, a polymer-based microring operating at around 890 nm wavelength was proposed and designed. A detailed analysis of modal characteristics of the slot waveguides were carried out from refractive index sensing. The relationships between the sensitivity and the waveguide height, width and slot width were analyzed. Conventional bend slot waveguide had a large propagation loss, which had a bad influence on the quality factor Q and the extinction ration of the microring. An asymmetric slot waveguide was designed which could make the mode propagate in the middle of the waveguide and then decrease the bending loss. A strip-slot mode converter based on multimode interference (MMI) structure was designed for better coupling between strip and slot waveguides. Simulations show that the sensitivity of the designed microring resonator could reach 109 nm/RIU.