Fiber-optic distributed sensing of hydrostatic pressure and temperature

Novel Optical Fiber Sensors for Simultaneous Pressure and Temperature Measurement

The compact size of optical fiber sensors compared to their electronic counterparts, alongside the dielectric properties of the silica glass from which optical fibers are typically fabricated, enables their operation across diverse environments. Consequently, optical fiber sensors have been successfully deployed for many years while maintaining low installation and maintenance costs. However, most commercially available optical fiber sensors are designed to measure only a single parameter. Is it possible to monitor hydrostatic pressure and temperature changes simultaneously and in real time? This question is being addressed by Gabriela Statkiewicz-Barabach, D.Sc. Eng., Associate Professor at Wrocław University of Science and Technology from the Department of Optics and Photonics at the Faculty of Fundamental Problems of Technology. The research is made possible through funding from the European Funds for a Modern Economy 2021 - 2027 (FENG) program under the Proof of Concept action implemented by the Foundation for Polish Science (FNP).

Simultaneous measurements of two distinct physical parameters, including hydrostatic pressure and temperature, are critical in applications such as oil and gas drilling operations, environmental water flow and status monitoring, geotechnics, and geothermal drilling. The commercialization potential of a fiber-optic system capable of monitoring these two parameters simultaneously over long distances or large areas with high spatial resolution appears to be substantial.

"The proposed concept will rely on Rayleigh scattering amplitude measurements, enabling distributed sensing over long distances - ranging from several to tens of meters - with exceptional spatial resolution of approximately 1 millimeter. Such resolution is unachievable using commercial fiber Bragg grating (FBG) sensors. Conversely, optical detector systems offering high spatial resolution are typically cross-sensitive to both temperature variations and structural strain - systems currently used, for example, in structural health monitoring of bridges or buildings. Unfortunately, because they respond simultaneously to temperature and strain changes, the resulting signal cannot differentiate between the contributions of these two distinct parameters. In our research, we aim to resolve this cross-sensitivity. To achieve this, we will utilize a custom side-hole birefringent optical fiber developed by our team, coupled with a novel detection system," explains Prof. Statkiewicz-Barabach.

As the researcher highlights, given the large market of potential end-users and the near absence of competing products, the technology developed by the team at Wrocław University of Science and Technology has the potential to fill an existing market gap both in Poland and internationally. Applications for this technology are expected to grow annually, particularly due to the small footprint of fiber sensors, which allows installation in tight spaces inaccessible to conventional sensors.

Prof. Statkiewicz-Barabach is conducting research on these new optical fiber sensors in collaboration with Agnieszka Bednarek, M.Sc. Eng., also from the Department of Optics and Photonics.

Gabriela Statkiewicz-Barabach, D.Sc. Eng., graduated from the Faculty of Fundamental Problems of Technology at Wrocław University of Science and Technology with a degree in Engineering Physics, specializing in Biomedical Engineering. After earning her PhD, she joined the Institute of Physics at Wrocław University of Science and Technology, where she subsequently obtained her habilitation degree (D.Sc.). She is currently an Associate Professor in the Department of Optics and Photonics within the Faculty of Fundamental Problems of Technology at Wrocław University of Science and Technology. She has principal investigator experience across multiple research projects, including Miniatura, Iuventus Plus, and Opus. Her research findings have been published in 48 articles in peer-reviewed international scientific journals, accumulating over 1,000 citations (excluding self-citations) with an h-index of 20. Her main research interests focus on optical fiber photonics, with an emphasis on fiber-optic sensors and optical fiber microstructuring technologies.