Fabrication of whispering gallery mode (wgm) micro resonator for temperature sensor

Abstract

Whispering Gallery Mode (WGM) resonators have garnered significant attention in recent years due to their exceptional sensitivity and potential in various sensing applications, particularly as temperature sensors. This study presented the study of WGM resonators as temperature sensors, with a focus on the fabrication process using fusion splicing and the tapered fiber coupling technique as WGM coupling system. The microresonator shape and diameter were optimized, resulting in a spherical-shaped WGM microresonator with a diameter of 260.960 ?m, which were chosen and demonstrated throughout this study. The narrowest tapered fiber, with a diameter of 1.27 ?m, was fabricated and is crucial in this study to achieve a 99% coupling efficiency between the tapered fiber and the microresonator. In addition, the distance between the tapered fiber and microresonator influences the coupling efficiency and plays a crucial role in enhancing their performance in temperature sensing throughout this study. The spherical WGM microresonator is demonstrated for temperature sensing, and its performance across a temperature range from 29°C to 35°C is observed, resulting in a sensitivity of approximately 0.015 nm/°C for heating and 0.019 nm/°C for the cooling process. Consequently, this study provides a clearer understanding of WGM microresonator sensitivity, stability, and fabrication simplicity, ultimately enabling the identification of an ideal diameter range for specific temperature sensing requirements. The findings underscore the potential of fusion splicer as alternative for WGM microresonator fabrication and tapered fiber coupling in creating highly sensitive and stable microresonators for temperature measurements, promising innovative solutions for a wide range of practical applications.