PDMS-based liquid-core optical fiber fluorescence pressure sensor

Optical fiber pressure sensors have become indispensable in various fields due to their unique advantages. Traditional sensors based on fiber Bragg gratings or Fabry-Pérot resonators offer high sensitivity and the ability to perform distributed measurements. However, these sensors often suffer from complex manufacturing processes and high costs. To address these challenges, we propose an innovative approach utilizing a polydimethylsiloxane (PDMS)-based liquid-core optical fiber probe for pressure sensing. The fiber probe is prepared by sealing a fluorescent dye solution within the PDMS-based hollow-core fiber and then inserting the end face of a silica optical fiber into it, which only relies on extremely simple fabrication operations and cost-effective materials. When integrated with an excitation laser and a fiber spectrometer, the sensor enables calibration and quantitative detection of pressure based on the correlation between pressure and the fluorescence intensity. The experimental results show that the sensor exhibits a high sensitivity of 400.508 a.u./N and a high resolution of 0.093 N, along with high detection accuracy, good repeatability and stability, rapid dynamic response, and excellent long-term stability within the 0–30 N load range. Moreover, it is capable of effectively monitoring various human activities, such as finger tapping and palm pressure, which are crucial for applications in medical monitoring, wearable devices, human activity monitoring, and smart products.