Micro-nano optical fiber coupled strain sensor

To realize high-precision strain sensing measurements, a strain sensor based on high-sensitivity micro-nano fiber coupling was proposed. Two single-mode optical fibers were stripped off from a coating layer and placed on an optical fiber pull-cone platform, and the two optical fibers were wound together. Then, the required pull cone parameters were set, and hydrogen flow was turned on. Then, the two optical fibers were pull-cone burned using a hydrogen flame to prepare the optical fiber coupler. The strain measurement was realized by using the strong evanescent field characteristic after coupling. Based on repeated measurements, it was concluded that the sensor has good reversibility. To overcome the cross-sensitivity problem, the interference dip has different sensitive characteristics with respect to temperature and strain, and a coefficient matrix is used to determine the influence of temperature on strain. The experimental results show that the strain sensitivity is 20.35 pm/με and the corresponding linear correlation coefficient is 99.9%. In contrast with other sensors, this strain sensor has high sensitivity, good stability, and low cost; further, it has substantial application value in building safety detection and other tasks.