Ding Zhenyang, Sun Keliang, Liu Kun, Jiang Junfeng, Yang Di, Yu Zhe, Li Jing, Liu Tiegen
Opt Express. 2018 May 14;26(10):13042-13054. doi: 10.1364/OE.26.013042.
We present a distributed refractive index (RI) sensor using tapered optical fibers in optical frequency domain reflectometry (OFDR). RI of the external medium surrounding the tapered optical fibers is measured by the optical frequency shifts of the local back-reflection spectra in OFDR. By a spectrum interpolation, we can increase the resolution of RI measurements without decreasing the sensing spatial resolution. In our experiments, we realize a truly distributed RI sensing with a 4.25 mm spatial resolution and 2.1 cm measurement distance. We calibrate the relationship between the optical frequency shifts of the local back-reflection spectra and RI variation. RI ranges from 1.3574 to 1.3686 and the sensitivity is about 8565 GHz/RIU (68.52 nm/RIU) in the presented sensor. We also measure RI variation in a glycerol solution diffusion to verify the capability of distributed RI sensing by the presented sensor.
我们展示了一种在光频域反射仪（OFDR）中使用锥形光纤的分布式折射率（RI）传感器。通过OFDR中局部背向反射光谱的光频移来测量锥形光纤周围外部介质的折射率。通过光谱插值，我们可以在不降低传感空间分辨率的情况下提高折射率测量的分辨率。在我们的实验中，我们实现了具有4.25毫米空间分辨率和2.1厘米测量距离的真正分布式折射率传感。我们校准了局部背向反射光谱的光频移与折射率变化之间的关系。在所展示的传感器中，折射率范围为1.3574至1.3686，灵敏度约为8565 GHz/RIU（68.52 nm/RIU）。我们还测量了甘油溶液扩散过程中的折射率变化，以验证所展示的传感器进行分布式折射率传感的能力。
