Poeggel, S,Duraibabu, D,Kalli, K,Leen, G,Dooly, G,Lewis, E,Kelly, J,Munroe, M

2015

September

Biosensors-Basel

Recent Improvement of Medical Optical Fibre Pressure and Temperature Sensors

Published

()

optical fibre sensors Fabry-Perot interferometer pressure sensors

5

432

449

This investigation describes a detailed analysis of the fabrication and testing of optical fibre pressure and temperature sensors (OFPTS). The optical sensor of this research is based on an extrinsic Fabry-Perot interferometer (EFPI) with integrated fibre Bragg grating (FBG) for simultaneous pressure and temperature measurements. The sensor is fabricated exclusively in glass and with a small diameter of 0.2 mm, making it suitable for volume-restricted bio-medical applications. Diaphragm shrinking techniques based on polishing, hydrofluoric (HF) acid and femtosecond (FS) laser micro-machining are described and analysed. The presented sensors were examined carefully and demonstrated a pressure sensitivity in the range of s(p) = 2-10 nm/kPa and a resolution of better than Delta P = 10 Pa (0.1 cm H2O). A static pressure test in 38 cm H2O shows no drift of the sensor in a six-day period. Additionally, a dynamic pressure analysis demonstrated that the OFPTS never exceeded a drift of more than 130 Pa (1.3 cm H2O) in a 12-h measurement, carried out in a cardiovascular simulator. The temperature sensitivity is given by k - 10.7 pm/K, which results in a temperature resolution of better than Delta T = 0.1 K. Since the temperature sensing element is placed close to the pressure sensing element, the pressure sensor is insensitive to temperature changes.

10.3390/bios5030432