Multipoint pressure sensing at up to 900?C using a fiber optic multimode interferometer

We demonstrate a multipoint optical fiber pressure sensor for high temperature operation using multimode interference. Each sensing element consists of a four-hole asymmetric multimode fiber acting as the pressure sensing fiber, spliced between two standard polarization-maintaining single mode fibers. Multiple sensing elements are serially connected for multipoint pressure sensing and demultiplexing is achieved using Fourier analysis. The spatial frequency associated with each sensing element is separated by having distinct optical path lengths. The pure silica material of the sensing fiber enables high-temperature operation. As a proof of concept, we demonstrate two-point pressure sensing at a temperature up to 900 degrees C with negligible crosstalk between the sensing elements and good stability. Our demonstrated sensor has potential applications in heavy industry where spatially resolved measurements of pressure at high temperature may lead to improvements in efficiency and safety.

Automated summary

In this study, we present a multipoint optical fiber pressure sensor for high temperature operation using multimode interference. The sensor consists of several sensing elements that are connected in series and demultiplexed using Fourier analysis. Each sensing element is made of a four-hole asymmetric multimode fiber and two standard polarization-maintaining single mode fibers. The sensor can operate at temperatures up to 900 degrees C and has potential applications in heavy industry for spatially resolved pressure measurements that can improve efficiency and safety.