International Science Index


Compact Optical Sensors for Harsh Environments


Optical miniaturized sensors with remote readout are required devices for the monitoring in harsh electromagnetic environments. As an example, in turbo and hydro generators, excessively high vibrations of the end-windings can lead to dramatic damages, imposing very high, additional service costs. A significant change of the generator temperature can also be an indicator of the system failure. Continuous monitoring of vibrations, temperature, humidity, and gases is therefore mandatory. The high electromagnetic fields in the generators impose the use of non-conductive devices in order to prevent electromagnetic interferences and to electrically isolate the sensing element to the electronic readout. Metal-free sensors are good candidates for such systems since they are immune to very strong electromagnetic fields and given the fact that they are non-conductive. We have realized miniature optical accelerometer and temperature sensors for a remote sensing of the harsh environments using the common, inexpensive silicon Micro Electro-Mechanical System (MEMS) platform. Both devices show highly linear response. The accelerometer has a deviation within 1% from the linear fit when tested in a range 0 – 40 g. The temperature sensor can provide the measurement accuracy better than 1 °C in a range 20 – 150 °C. The design of other type of sensors for the environments with high electromagnetic interferences has also been discussed.

[1] D. A. Krohn, T. W. MacDougall, and A. Mendez, “Fiber Optic Sensors: Fundamentals and Applications,” SPIE, 2015.
[2] B. Guldimann, “Micromachined fiber optic accelerometer based on intensity modulation”, PhD thesis, University of Neuchatel, 2001.
[3] L. Chongyu, H. Luo, S. Xiong, and H. Li, "Investigation of a fiber optic accelerometer based on FBG-FP interferometer," Proc. SPIE 9297, 2014.
[4] Y-G. Lee, D-H. Kim, and C-G. Kim, "Performance of a single reflective grating-based fiber optic accelerometer” Measurement Science and Technology, vol. 23, no. 4, 2012.
[5] Z-Z. Yang, H. Luo, and S-D. Xiong, "High sensitivity fiber optic accelerometer based on folding F-P cavity," Proc. SPIE 8914, International Symposium on Photoelectronic Detection and Imaging: Fiber Optic Sensors and Optical Coherence Tomography, 2013.
[6] F. Peng, J. Yang, B. Wu, Y. Yuan, X. Li, A. Zhou, and L. Yuan, "Compact fiber optic accelerometer," Chin. Opt. Lett. vol. 10, no. 1, 2012.
[7] M. F. Sultan, M. J. O’Rourke, “Temperature sensing by band gap optics absorption in semiconductors,” Proc. SPIE 2839, pp. 191-202, 1996.
[8] Y. Zhao, M. Rong, and Y. B. Liao, “Fiber optic temperature sensor used for oil well based on semiconductor optical absorption,” IEEE Sensors Journal, vol. 3, no. 4, pp. 400-403, 2003.