Journal of Micromechanics and Microengineering: Structures, Devices and Systems vol:19 issue:11
Fiber optical pressure sensors show great promise in monitoring harsh environments as sensitive readout electronics can be located remotely. In this paper, a process based on thin film techniques and focused ion beam (FIB) machining is demonstrated that allows the fabrication of a Fabry–Pérot interferometer-based sensor directly on top of an optical fiber. Besides its extremely small size and rugged monolithic construction, the silica-based sensor has the advantage that thermal mismatch is minimal and a vacuum reference pressure cavity is present, enabling application in high-temperature environments. Operation in an environment up to 600 °C is demonstrated. Furthermore, a possible route toward mass fabrication of such sensors is presented, avoiding the need for a FIB operation.