Angle-polished fiber-integrated submicron wall microbubble WGM resonator for pressure and temperature sensing

This paper presents an angle-polished single-mode fiber-integrated submicron wall microbubble resonator (APSMF-MBR). Utilizing an improved arc-discharge method, a microbubble structure with a minimum wall thickness of only 765 nm was successfully fabricated. The fiber endface was meticulously polished to an angle of 81.5°, enabling the partial coupling of incident light propagating tangentially along the fiber core onto the microbubble surface, thereby exciting the whispering gallery mode (WGM). Due to its ultra-thin wall design, the device demonstrated a high pressure sensitivity of 913 pm/MPa and a low temperature sensitivity of 3.163 pm/°C in sensing tests. Additionally, the angle-polished fiber combined with fiber Bragg gratings (FBGs) effectively mitigates temperature interference in pressure measurements, thereby enhancing measurement accuracy. Experimental results demonstrate that this angle-polished single-mode fiber, integrated with a submicron wall microbubble resonator, exhibits high pressure sensitivity and low temperature sensitivity, providing what we believe to be a novel and viable solution for measuring pressure and temperature.