基于光子晶体平板传导共振模的低功率光开关

Low power optical switch based on guided resonance of photonic crystal slab

利用严格耦合波算法计算了二维光子晶体平板结构随角度变化透过谱和波长变化透过谱,研究了透过谱上传导共振峰与二维光子晶体平板能带结构的关系。利用共振传导模的低透过和高Q值的特点,设计了基于磷化铟材料的工作在1550 nm波长附近的角度分辨和波长分辨的光子晶体光开关。理论模拟结果表明,该结构透过谱上传导共振峰品质因子可达10~3,非线性折射率变化为10^(-4)即可实现开关对比度接近100%。当信号光或泵浦光分别与光子晶体平板传导共振模耦合时,由于共振耦合使得泵浦光场增强,需要泵浦能量仅为184 fJ,为目前所知能量最低的光开关。

The wavelength and angle dependent optical transmission of two-dimensional photonic crystal slab are calculaled using rigorous coupled wave analysis （RCWA） method. The relationship between guided resonance of spectrum and the band structure of two-dimensional photonic crystal slab is investigated. Based on InP material photonic crystal slab, angle resolved and wavelength resolved optical switches are designed utilizing the characterization of low transmission and high quality factor of guided resonance. These switches operate at the wavelength of 1550 nm. It shows that the quality factor of guided resonance mode in the transmission spectrum can reach 10^5, and achieve an on-off contrast of nearly 100% with the nonlinear refractive index change of 10^-4. As the signal light and pump light couple with the guided resonance modes of photonic crystal slab respectively, the field intensity of pump light is enhanced, and the pump energy is reduced to only 184 fJ. To our knowledge, this is the lowest energy needed for optical switcher.