Li Li, Jiang Chao, Hu Chuanju, Gao Jiawei, Deng Longfeng, Cao Tingshui, Li Hong
College of Physics and Electronic Science, Hubei Normal University, Huangshi, Hubei 435002, China.
Rev Sci Instrum. 2023 Jul 1;94(7). doi: 10.1063/5.0157555.
A high sensitivity strain sensor using a sandwich structure of "single mode fiber (SMF)-few mode fiber (FMF)-single mode fiber (SMF)" was proposed and experimentally validated. The designed sensor is achieved by splicing a segment of FMF between two segments of SMFs, and then using a fiber optic fusion tapering machine to double the length of FMF. Introducing tapered optical fibers into the structure to excite more evanescent waves improves the sensitivity of the sensor to the surrounding environment. In addition, due to the fact that the FMF is tapered into a very fine shape, the tensile stress applied to the FMF will increase. Therefore, conical FMF has excellent stress concentration ability, which is easily deformed under stress, thus achieving a high strain sensitivity of -23.9 pm/με. Finally, a cascaded FBG was used to compensate for the temperature cross-sensitivity of the sensor. This strain sensor with an extremely simple structure and high sensitivity has wide application value in the industry.
提出了一种采用“单模光纤（SMF）-少模光纤（FMF）-单模光纤（SMF）”三明治结构的高灵敏度应变传感器，并进行了实验验证。所设计的传感器是通过在两段单模光纤之间熔接一段少模光纤，然后使用光纤熔锥机将少模光纤的长度加倍来实现的。在结构中引入锥形光纤以激发更多的倏逝波，提高了传感器对周围环境的灵敏度。此外，由于少模光纤被拉制成非常细的形状，施加在少模光纤上的拉应力会增加。因此，锥形少模光纤具有优异的应力集中能力，在应力作用下容易变形，从而实现了-23.9 pm/με的高应变灵敏度。最后，使用级联光纤布拉格光栅（FBG）来补偿传感器的温度交叉灵敏度。这种结构极其简单且灵敏度高的应变传感器在工业中具有广泛的应用价值。
