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Optical Fiber Fabry-Pérot Micro-Displacement Sensor for MEMS In-plane Motion Stage



Yong Sik Kim, Nicholas Dagalakis, Young-Man Choi


Fabry-Perot interferometer sensors have been widely used in Micro-Electro-Mechanical-Systems (MEMS) due to high displacement accuracy and immunity to electromagnetic noises, but they are still limited by micro scale measurement range. In this paper, a Fabry-Perot interferometer in-plane displacement sensor is proposed for measuring the displacement of MEMS devices utilizing a polished optical fiber and a modulated laser source. The polished optical fiber and a sidewall of a MEMS device form an optical cavity for the proposed sensor. The sinusoidal phase modulation with inflection point searching enables the proposed sensor to measure displacements larger than the wavelengths of the laser light in real time. The experimental results show that the proposed displacement sensor has a capability to measure displacements larger than 3 µm and it shows the measurement error less than 35 nm. The proposed displacement sensor is then embedded on a single degree-of-freedom MEMS motion stage and tested to monitor its displacement in real time.
Journal of Microelectronic Engineering


Fabry-Perot interferometry, distributed feedback laser, phase lock, sinusoidal phase modulation, MEMS, optical fiber, displacement sensor


Kim, Y. , Dagalakis, N. and Choi, Y. (2018), Optical Fiber Fabry-Pérot Micro-Displacement Sensor for MEMS In-plane Motion Stage, Journal of Microelectronic Engineering, [online],, (Accessed May 27, 2024)


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Created February 27, 2018, Updated October 12, 2021