Analysis of Single, Cascade, and Cascade Coating of Microbottle Resonator With Sensing Application

This experimental paper explored the potential of the microbottle resonator (MBR) as a sensor with different structures and conditions. The silica fiber SMF-28 is used to form the bottle structure by a method known as “soften-and-compress.” Three different MBR structures with similar length $L_b$, stem diameter of $D_s$, and bottle diameter of $D_b$ are formed, classed as single, cascade and cascade coating MBR. The cascade coating MBR was used to apply polyvinyl alcohol (PVA) for the coating procedure. The transmitted power was observed in all MBR conditions, where the structure and coating may influence the resonator to have a low power value, ≥ 20 dBm. The performance of the MBRs as sensors is then represented by four parameters: sensitivity, linearity, stability, and repeatability from wavelength shift and transmitted spectral evaluation. Even though the cascade-coating MBR showed the lowest power value, it may influence to have remarkable performance through an evaluated parameter.