Hybrid Miniature Fabry-Perot Sensor with Dual Optical Cavities for Simultaneous Pressure and Temperature Measurements
Hyungdae Bae, Yun David, Haijun H. Liu, Douglas A. Olson, Miao Yu
We present a miniature dual-cavity Fabry-Perot sensor fabricated at the tip of an optical fiber for simultaneous pressure and temperature measurements. The pressure sensing cavity is an extrinsic air cavity created on a polymer housing by using an optically aligned UV-molding process. A metal/polymer composite diaphragm is exploited as the pressure transducer for achieving a high pressure sensitivity while maintaining a miniature sensor size. Another intrinsic polymer/silica cavity is used for temperature sensing. The added polymer layer makes it possible to achieve a high temperature sensitivity with a short cavity length due to the large thermal expansion of the polymer. The overall sensor size is around 150 µm in diameter and 343 µm in length. Experimental study shows that the sensor exhibits a good linearity over a pressure range of 6.89 kPa to 27.58 kPa with a pressure sensitivity of 0.0122 µm/kPa at 26°C, and a temperature range of 26.0 °C to 50.0 °C with a temperature sensitivity of 0.0029 µm/°C. An optical signal processing method is developed to retrieve the two cavity length changes, which is demonstrated to have a better resolution and a faster speed than the conventional method. The sensor is expected to benefit many fronts that require simultaneous pressure and temperature measurements with minimum intrusiveness, especially for biomedical applications.
, David, Y.
, Liu, H.
, Olson, D.
and Yu, M.
Hybrid Miniature Fabry-Perot Sensor with Dual Optical Cavities for Simultaneous Pressure and Temperature Measurements, Journal of Lightwave Technology, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=915034
(Accessed December 6, 2023)