Comparative Characterization Study of High-Q Optical Microbottle Resonators via Tapered Fibre Coupling at Neck and Maximum Curvature Regions

Abstract

Whispering gallery modes (WGM) such as microbottle resonators is a miniature light confining photonics device and are a promising component in photonic systems such as sensors, lasers, and optical filters due to their efficient light confinement and compact geometry. However, the effect of coupling position on their optical performance remains insufficiently explored. This study investigates the fabrication and characterization of optical microbottle resonators using tapered fibre coupling at two regions which are the neck and the maximum curvature. The microbottles were produced through controlled heating and surface-tension shaping of single-mode optical fibres, followed by precise light coupling via a tapered fibre. Experimental results show Q-factors of 12,492 at the neck and 16,843 at the maximum curvature, indicating stronger confinement and reduced scattering losses in the latter. These findings demonstrate the influence of coupling position on resonator performance and support the design of efficient microresonators for advanced photonic applications. Through the lens of Tawhidic epistemology, the ability of such microscopic structures to precisely confine and guide light reflects the immense power and wisdom of Allah.