Study by simulation and realization of a fiber optic pressure sensor based on a PDMS flexible µ-membrane

Fiber optic pressure sensors operate on various interferometric principles, such as amplitude modulation and polarization variation. In this study, we have developed and implemented a Fabry-Pérot interferometric sensor employing an innovative technique for membrane fabrication. The sensor utilizes a μ-cavity formed at the terminus of a multimode optical fiber through a chemical etching process. The first reflecting surface is established at the interface (core/air), while the second reflection takes place at the polymeric μ-membrane within polydimethylsiloxane (PDMS), serving as the second interface (PDMS/Air). The μ-cavity exhibits dimensions of up to 63 μm in depth and 83 μm in base diameter, with a membrane thickness of approximately 6 μm. The pressure and temperature sensitivity of the sensor are measured at − 51.8 nm/KPa and 0.3 nm/°C, respectively. The performance of the developed sensor is comprehensively characterized through an analytical study and simulation employing the finite element method COMSOL.