Lei Ting, Poon Andrew W
Photonic Device Laboratory, Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China.
Opt Express. 2011 Oct 24;19(22):22227-41. doi: 10.1364/OE.19.022227.
We model and analyze coupled-resonator optical waveguide (CROW) based refractive index (RI) sensors using pixelized spatial detection. Our modeled cascaded Fabry-Perot (FP) CROWs reveal that the intra-band states mode-field distributions vary upon effective RI change at a single wavelength. The spatial Fourier transform of the CROW mode-field distributions, with each cavity field intensity integrated as a pixel, shows spatial frequency peak shift, which constitutes the basis of such a spatial domain sensor. The spatial domain sensing performance depends on the cavity number, the cavity length and the inter-cavity coupling. Our modeled 21-element CROW sensor attains a detection limit of 10(-4) refractive index unit (RIU) with a sensing dynamic range of 10(-3) RIU. Detailed analysis of the spatial frequency harmonic peak amplitude variation further suggests an improved detection limit. Finite-difference time-domain (FDTD) simulations of an 11-element microring CROW device shows sensitivity consistent with the FP modeling.
我们使用像素化空间检测对基于耦合谐振器光波导（CROW）的折射率（RI）传感器进行建模和分析。我们建模的级联法布里 - 珀罗（FP）CROW表明，在单个波长下，带内状态模式场分布会随着有效RI的变化而变化。将每个腔场强度作为一个像素进行积分的CROW模式场分布的空间傅里叶变换显示出空间频率峰值偏移，这构成了这种空间域传感器的基础。空间域传感性能取决于腔的数量、腔的长度和腔间耦合。我们建模的21元件CROW传感器实现了10^(-4)折射率单位（RIU）的检测限，传感动态范围为10^(-3)RIU。对空间频率谐波峰值幅度变化的详细分析进一步表明检测限有所提高。对一个11元件微环CROW器件的时域有限差分（FDTD）模拟显示出与FP建模一致的灵敏度。
