从理论和实验上研究了一种价格低廉、操作简单、可用于多点并行测量的液体折射率光纤传感器。该传感器采用分路器进行预分光, 利用高稳定放大自发辐射光源作为光源、普通光功率计作为光电探测器, 以熔融拉锥光纤作为传感单元。建立了一个简单模型, 分析了芯层所携带的光功率占总的光功率的比值随外部介质折射率变化的关系。实验上对不同折射率样品的传输损耗进行了测量, 采用对比方法作出了传输损耗随折射率变化的定标曲线。实验结果表明：外部介质折射率越高, 传输损耗越大。并验证了反射器（光纤布拉格光栅）的引入能够有效的提高系统的灵敏度。

A new refractive index fiber optic sensor with low cost, easy operation and the capability of multipoint parallel measurement is explored. A splitter is used in the refractive index fiber optic sensor to achieve multipoint parallel measurement. A high stable amplified spontaneous emission light source and three optical power meters are used as broadband source and detectors, respectively. A simple model is established, and the relation between the ratio of the light power carried by the core versus the total light power of a fiber and the external refractive index (RI) is analyzed in detail. In the experiment, the transmission losses of sample solution with different refractive indices are measured, the calibration curve between transmission loss (TL) and RI by comparison is obtained. It is found that the higher the RI is, the bigger the TL is. The experiment verifies that it can improve the system sensitivity greatly by introducing a fiber Bragg grating.