Fiber Loop Ring-Down Refractive Index Sensor Based on High- $Q$ Photonic Crystal Cavity
Fiber Loop Ring-Down Refractive Index Sensor Based on High- $Q$ Photonic Crystal Cavity
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DOI：
10.1109/jsen.2014.2305971
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发表时间：
2014-02
影响因子：
4.3
通讯作者：
Ya‐nan Zhang;Yong Zhao;Di Wu;Qi Wang
中科院分区：
文献类型：
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作者：
Ya‐nan Zhang;Yong Zhao;Di Wu;Qi Wang
提出了一种基于高品质光子晶体腔光纤环衰荡的新型超紧凑折射率传感器。在我们提出的器件结构中，我们在线性波导中插入一对两个空气孔作为两个反射器，并在两个反射器之间定义一个点缺陷以形成纳米腔。由于输出共振光谱对孔中渗透介质引起的小折射率变化非常敏感，因此衰荡时间以及辐射强度将是特定频率下输入光的相对折射率的函数。为了提高系统的灵敏度，通过调节空气孔的半径和两个反射镜之间的间距来优化纳米腔的Q值。利用时域有限差分法对折射率传感器的特性进行了分析和仿真。实验结果表明，该方法可实现折射率的准线性测量，灵敏度为20.34 ms/折射率单位，Q值为605。此外，通过使用多个工作频率，传感范围可以扩展到1.330-1.400。
This paper proposed a novel ultracompact refractive index sensor formed by a high-quality (Q) photonic crystal (PhC) cavity-based fiber loop ring-down. In our proposed device configuration, we insert one pair of two air holes into the linear waveguide as two reflectors, and a point defect was defined between the two reflectors to form a nanocavity. Since the output resonant spectrum was extremely sensitive to a small refractive index variance attributed to the medium infiltrated in the holes, the ring-down time as well as the radiation intensity would be a function of the relative refractive index for input light at certain frequency. To improve the system sensitivity, the Q -factor of nanocavity was optimized by adjusting the radii of all air holes and the spacing between the two reflectors. The properties of the refractive index sensor were analyzed and simulated using the finite-difference time-domain method. Results showed that a quasi-linear measurement of refractive index was achieved with sensitivity of 20.34 ms per refractive index unit and Q -factor of 605. In addition, the sensing range could be broadened to 1.330-1.400 by using multiple operating frequencies.