199 / 2024-03-12 21:50:13

Self-reference sensing scheme by mode splitting in a microfiber coil resonator with three turns

microfiber coil,resonator,mode splitting,refractive index sensing,angular velocity sensing

The phase shift readout scheme based on optical ring resonator is currently considered to be one of the most sensitive sensing schemes available. Its potential applications in fields such as temperature sensing, refractive index sensing, and angular velocity sensing have garnered extensive attention. However, in applications that use the optical resonant cavity for purposes other than temperature sensing, temperature drift can act as a source of noise. This can result in uncertainty errors being introduced to the sensor. As a self-referenced sensing scheme, mode splitting has the potential to minimize the influence of external environmental factors, such as temperature fluctuations. Our recent findings indicate that fine-tuning the coupling state within a microfiber coil resonator with three turns can effectively enhance the degeneracy of resonant modes and subsequently induce a controlled mode-splitting state. We have presented the distribution of phase shift of the split resonant modes in a microfiber coil with three turns respect to the variation of coupling parameters. The sensing mechanism of mode splitting based on MCR has been deliberated, and its validity has been demonstrated through refractive index and angular velocity sensing. A three-turn microfiber coil resonator with a radius of 1 mm and a loss coefficient of 0.02/mm is assumed. When the refractive index of the medium surrounding the MCR decreased or increased by 0.05 from the initial value of 1.25, the phase difference of the two split modes decreased by 0.88 and increased by 0.67, respectively. When the MCR rotates clockwise with an angular velocity of \(5\times10^{10}(^{\circ}/s)\), the phase difference of the two split modes in the clockwise and counterclockwise directions increased by 0.57 and decreased by 0.69, respectively.