High-sensitivity hydraulic pressure sensor realized with PDMS film-based Fabry-Perot interferometer

A high-sensitivity hydraulic pressure sensor with polydimethylsiloxane (PDMS) film-based Fabry-Perot interferometer (FPI) is experimentally demonstrated. The sensor is fabricated by splicing a single mode fiber (SMF) with a section of hollow core fiber (HCF), then filling PDMS into the HCF. By capillary effect, a thin PDMS film up to 33.75 μm is achieved, which works as a reflector of the FPI. The sensor is compact for the length of the FPI cavity as short as 137.79 μm. Due to excellent elasticity of the PDMS film, the sensor’s sensitivity is enhanced. The experimental results indicate that a hydraulic pressures sensitivity as high as 11.4 nm/kPa can be achieved within the range from 0 to 440 Pa with the detective limitation of 50 Pa. Moreover, ultra-compact device size and optical fiber configuration make it possible to sense hydraulic pressure sensitively under the harsh environment.