报道了一种基于多模干涉理论的光纤折射率传感器，其传感器结构由两段单模光纤中嵌入一小段无包层多模光纤组成。研究了传感器的传输光谱与折射率的关系。实验结果表明，当外界折射率变化范围为1.336～1.372时，传感器获得灵敏度为5.4×10-5 RIU(RIU为折射率单元)。该传感器在生物化学测量中有比较好的应用前景。

A fiber-optic refractometer based on the multimode interference in the singlemode-multimode core-singlemode fiber structure is demonstrated. The refractive index dependence of re-imaging resonant wavelength shift of the devices is investigated. It shows that the proposed sensor has a measurement resolution of 5.4×10-5 for the change of refractive indices from 1.336 to 1.372. The proposed sensor has great potential for biological and chemical applications.