High-Pressure Sensors Based on Laser-Manufactured Sintered Silicon Carbide

Abstract

In this work Sintered Silicon Carbide (S-SiC) samples have been used to fabricate fiber-optic-coupled pressure sensors. The sensor structure reproduces a low-finesse Fabry–Perot (FP) interferometer. Laser manufacturing of cylindrical S-SiC samples was performed to define the thin membrane geometry of sensors. FP cavity is defined by the end-face of a single mode fiber and the S-SiC diaphragm surface. Hence, pressure is evaluated by measuring the cavity depth by a dedicated optoelectronic system coupled to the single mode fiber. Exploiting the excellent properties of S-SiC, in terms of high hardness, low thermal expansion, and high thermal conductivity, realized devices have been characterized up to 20 MPa. Experimental results demonstrate that produced sensors exhibit a non-linearity around ±0.6%F.S. and a high input dynamics. The all-optic sensing system proposed in this work would represent a good alternative to conventional solutions based on piezoelectric effects, overcoming the drawback related to electromagnetic interference on the acquired signals. In addition, the mechanical characteristics of S-SiC allow the use of the sensor in both automotive and aerospace hostile environments as pressure monitors in combustion engines.