A highly efficient tunable optical filter of liquid crystal (LC) optical micro-ring resonator (MRR) was proposed. The 4-μm-radius ring consists of a silicon-oninsulator (SOI) asymmetric bent slot waveguide with a LC cladding. The geometry of the slot waveguide resulted in the strong electro-optic effect of the LC, and therefore induced an increase in effective refractive index by 0.0720 for the quasi-TE mode light in the slot-waveguide. The ultra-wide tuning range (56.0 nm) and large free spectral range (FSR) (~28.0 nm) of the optical filters enabled wavelength reconfigurable multiplexing devices with a drive voltage of only 5 V. The influences of parameters, such as the slot width, total width of Si rails and slot shift on the device’s performance, were analyzed and the optimal design was given. Moreover, the influence of fabrication tolerances and the loss of device were both investigated. Compared with state-of-the-art tunable MRRs, the proposed electrically tunable micro-ring resonator owns the excellent features of wider tuning ranges, larger FSRs and ultralow voltages.

当前以电子作为信息载体的微电子技术遭遇到发展瓶颈。光传输具有带宽大、速率高的特点, 将光子载体与电子载体相结合是未来信息传输发展的必然趋势。波导与光纤的高效耦合是实现光电子集成的关键。文章介绍了国内外几种典型耦合器的最新进展, 包括楔形耦合器、GRIN(渐变折射率)透镜耦合器和垂直光栅耦合器, 并对它们的性能指标、优缺点进行了比较分析, 对进一步提高耦合效率的可行性进行了展望。结果表明, 垂直光栅耦合器具有耦合效率高、带宽大、工艺成熟、工艺容差大和耦合步骤简单的优势, 在光通信与集成光电子学领域有着广阔的应用前景。