Monitoring of pressurized pipelines with whispering gallery mode-based sensors

Abstract

The purpose of this work is to explore the use of optical resonators based on the Whispering Gallery Mode phenomenon (WGM), to determine the variation of the internal pressure of a pipeline due to leaks. Numerical experiments were performed to determine the sensitivity of disk-shaped optical resonators embedded in the wall of the pipe. A change in the internal pressure causes mechanical stress in the pipe wall and therefore a strain that is transferred to the optical resonator. This strain can be related to the shift of the optical modes (WGM shift) to determine the sensitivity of the sensor. The parameters investigated include the size of the resonator and the location within the thickness of the pipe wall. The results show a linear behavior of the WGM shift with the applied pressure, as well as a quadratic increase of the sensitivity with the resonator diameter.