Xie Yiwei, Zhang Ming, Dai Daoxin
Centre for Optical and Electromagnetic Research, State Key Laboratory for Modern Optical Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, Zijingang Campus, Hangzhou 310058, China.
Ningbo Research Institute, Zhejiang University, Ningbo 315100, China.
Sensors (Basel). 2020 May 5;20(9):2640. doi: 10.3390/s20092640.
A design rule for a Mach-Zehnder interferometer (MZI) sensor is presented, allowing tunable sensitivity by appropriately choosing the MZI arm lengths according to the formula given in this paper. The present MZI sensor designed by this method can achieve an ultra-high sensitivity, which is much higher than any other traditional MZI sensors. An example is given with silicon-on-insulator (SOI) nanowires and the device sensitivity is as high as 10 nm/refractive-index -unit (or even higher), by choosing the MZI arms appropriately. This makes it possible for one to realize a low-cost optical sensing system with a detection limit as high as 10 refractive-index-unit, even when a cheap optical spectrum analyzer with low-resolution (e.g., 1 nm) is used for the wavelength-shift measurement.
本文提出了一种马赫-曾德尔干涉仪（MZI）传感器的设计规则，通过根据本文给出的公式适当选择MZI臂长来实现灵敏度的可调。采用该方法设计的当前MZI传感器可实现超高灵敏度，远高于任何其他传统MZI传感器。文中给出了一个基于绝缘体上硅（SOI）纳米线的示例，通过适当选择MZI臂，器件灵敏度高达10 nm/折射率单位（甚至更高）。这使得即使使用低分辨率（如1 nm）的廉价光谱分析仪进行波长偏移测量，也能够实现检测限高达10折射率单位的低成本光学传感系统。
