研究了一种基于频移干涉原理的新型连续波光纤腔衰荡液体折射率传感方法,采用熔融拉锥方法制作锥形光纤传感探头,并对不同浓度下液体的折射率进行了实验研究。结果表明,溶液质量分数小于9%时,NaCl和葡萄糖溶液的探测灵敏度分别为3.779 dB·RIU ^-1和6.413 dB·RIU ^-1(RIU为折射率单元),系统的最低检测限为10 ^-4。在40 min的连续观察时间内,腔内损耗的标准差小于0.4%,系统表现出良好的稳定性。与传统技术相比,该技术无需高速探测设备,降低了对硬件设备的要求。该系统具有结构简单、成本低、灵敏度高等优点,在化学探测、生物传感领域具有一定的应用前景。

A novel continuous-wave fiber optics cavity ring-down refractive index sensing method based on the frequency-shifted interferometry is researched. We made a sensor by using a section of fused fiber optics taper in the fiber ring-down cavity to experimentally study the refractive index of liquids at different concentrations. The experimental results show that the detection sensitivities of NaCl and glucose solutions are 3.779 dB·RIU -1 and 6.413 dB·RIU -1 (RIU is refractivity unit), respectively, in the range of solution mass fraction less than 9%, and the minimum detection limit of the system is 10 -4. The relative deviation of measured cavity loss is less than 0.4% over 40 min continuous observation, showing good stability. In contrast to conventional cavity ring-down schemes, the frequency-shifted interferometry does not require fast detection electronics and reduces the need for hardware devices. The sensing system has the advantages of simple structure, low cost and high sensitivity, and has some application prospects of chemical detection and biosensing.