Development of prototype fiber-optic-based Fizeau pressure sensors with temperature compensation and signal recovery by coherence reading

A range of prototype fiber-optic-based Fizeau interferometric pressure sensors with temperature compensation and signal recovery by dual-wavelength coherence reading have been developed. A separate fiber-optic-based Fizeau temperature sensor with similar cavity length was incorporated into the pressure sensor to allow the pressure measurement to be corrected for the temperature dependence of the pressure probe. The pressure and temperature probes were multiplexed spatially. For the low-pressure sensor, the obtained range to resolution ratio and the accuracy were ~6.7×10³:1 and better than ±1 percent over a pressure range of 0-0.48 bar, respectively. For the medium pressure sensor, the achieved range to resolution ratio and the overall accuracy were 3.6×10⁴:1 and ±0.15 percent over a full-pressure range of ~10 bar. For the high pressure sensor, a range to resolute ratio of ~1.67×10⁴:1 and an overall measurement accuracy of ±0.69 percent over a pressure range of ~1000 bar have been achieved. Due to the universality of the signal-processing scheme based on the dual-wavelength coherence-reading technique, the signal-processing box can be compatible with a range of sensors illuminated by the sources with similar central wavelengths. This study would be readily used to develop a range of commercial fiber-optic pressure sensors with similar optical path differences, interrogated by a universal signal-processing box, for different applications