Janik Monika, Koba Marcin, Król Krystian, Mikulic Predrag, Bock Wojtek J, Śmietana Mateusz
Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warszawa, Poland.
Department of Metrology and Optoelectronics, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk, Poland.
Sensors (Basel). 2020 Apr 24;20(8):2431. doi: 10.3390/s20082431.
This work discusses sensing properties of a long-period grating (LPG) and microcavity in-line Mach-Zehnder interferometer (µIMZI) when both are induced in the same single-mode optical fiber. LPGs were either etched or nanocoated with aluminum oxide (AlO) to increase its refractive index (RI) sensitivity up to ≈2000 and 9000 nm/RIU, respectively. The µIMZI was machined using a femtosecond laser as a cylindrical cavity (d = 60 μm) in the center of the LPG. In transmission measurements for various RI in the cavity and around the LPG we observed two effects coming from the two independently working sensors. This dual operation had no significant impact on either of the devices in terms of their functional properties, especially in a lower RI range. Moreover, due to the properties of combined sensors two major effects can be distinguished-sensitivity to the RI of the volume and sensitivity to the RI at the surface. Considering also the negligible temperature sensitivity of the µIMZI, it makes the combination of LPG and µIMZI sensors a promising approach to limit cross-sensitivity or tackle simultaneous measurements of multiple effects with high efficiency and reliability.
本文讨论了长周期光栅（LPG）和微腔在线马赫曾德尔干涉仪（µIMZI）在同一单模光纤中同时产生时的传感特性。LPG要么经过蚀刻，要么用氧化铝（AlO）进行纳米涂层处理，以分别将其折射率（RI）灵敏度提高到约2000和9000 nm/RIU。µIMZI是使用飞秒激光在LPG中心加工出一个圆柱形腔（d = 60 µm）制成的。在对腔体内和LPG周围各种折射率进行的透射测量中，我们观察到了来自两个独立工作传感器的两种效应。这种双重操作对两个器件的功能特性均无显著影响，尤其是在较低折射率范围内。此外，由于组合传感器的特性，可以区分出两种主要效应——对体积折射率的灵敏度和对表面折射率的灵敏度。考虑到µIMZI的温度灵敏度可忽略不计，这使得LPG和µIMZI传感器的组合成为一种很有前景的方法，可用于限制交叉灵敏度或高效可靠地处理多种效应的同时测量。
