All-SiC Fiber-Optic Sensor Based on Direct Wafer Bonding for High Temperature Pressure Sensing

Abstract This paper presents an all-SiC fiber-optic Fabry-Perot (FP) pressure sensor based on the hydrophilic direct bonding technology for applications in harsh environment. The operating principle, fabrication, interface characteristics, and response test of proposed are discussed. FP cavity is formed by hermetically two-layer SiC wafers, including a thinned diaphragm wafer with etched cavity. White light interference used detection demodulation signals. Experimental results demonstrate sensing capabilities range up to 800 kPa. structure without any intermediate layer can avoid failure caused thermal expansion coefficient mismatch therefore has great potential measurement high temperature environments.