Fiber optic multipoint pressure and temperature sensing system using BOF/DWPR

A novel fiber optic sensor using 'BOF' has been developed by vapor deposition of dielectric BPF on an end face of a single-mode fiber, as BPF on fiber-end (BOF), of which the reflection spectrum varies according to its temperature and pressure. The spectrum shift is obtainable as the ratio of reflectance at both sides of the BOF center wavelength, which is derived from the dual wavelength impulse responses of the sensor network obtained on the PN code correlation scheme. It is called dual wavelength push-pull ratiometric reflectometry (DWPR). The resulting multipoint temperature and pressure sensing operation will be demonstrated.