Absolute fiber-optic pressure sensing for high-temperature applications using white light interferometry

Fiber-optic pressure sensors allow rugged high-temperature and ultra-miniature pressure monitoring in harsh environments. However, simple light power based readout suffers from bending losses and light source fluctuations. This paper presents a differential technique based on white light interferometry to alleviate this problem. White light spectroscopic measurements have been performed on absolute Fabry-Pérot pressure sensors fabricated at the tip of multi-mode and single mode optical fibers. Bending loss sensitivity is demonstrated to be reduced with a factor of 79% by using the proposed differential spectroscopic technique.