Catalano E, Vallifuoco R, Bernini R, Zeni L, Minardo A
Opt Express. 2022 Oct 24;30(22):39868-39876. doi: 10.1364/OE.467839.
We demonstrate the use of non-adiabatic tapers for refractive index sensing in optical fibers based on Brillouin scattering. By exciting higher order optical modes along the taper, the Brillouin gain spectrum becomes multipeaked, where each peak exhibits a different sensitivity to the refractive index of the surrounding medium. By this method, we demonstrate a sensitivity enhancement of the Brillouin frequency shift to refractive index changes by a factor of ≈ 4, compared to an adiabatic taper with the same waist diameter. Furthermore, the use of the spectral difference between two Brillouin gain peaks provides a temperature-independent measurement of the external refractive index.
我们展示了基于布里渊散射的非绝热光纤折射率传感的应用。通过沿着锥形光纤激发高阶光学模式，布里渊增益谱变得多峰化，其中每个峰对周围介质的折射率表现出不同的灵敏度。通过这种方法，与具有相同腰径的绝热锥形光纤相比，我们证明了布里渊频移对折射率变化的灵敏度提高了约4倍。此外，利用两个布里渊增益峰之间的光谱差异可以实现与温度无关的外部折射率测量。
