为满足燃气轮机叶尖间隙测量需要，设计了一种双圈同轴式光纤位移传感器。根据光纤对光强耦合原理得到了传感器探头有无准直透镜时双圈同轴光纤束的光强调制特性函数，分析了透镜对反射式光纤位移传感器测量特性的影响，仿真评估了透镜透射效率及光的干涉对传感器测量结果的影响。进行了光纤束前端有无准直透镜情况下的静态测量实验及模拟烟雾干扰实验。结果表明，传感器线性测量范围约为2.6 mm，且具有较好的抗烟雾干扰能力。为反射式光纤位移传感器在燃气轮机叶尖间隙复杂环境下的测量应用提供了参考。

In order to meet the measurement requirements of gas turbine tip clearance, the displacement optical sensor with two-circle reflective coaxial fiber probe is designed. Output functions of the fiber sensor without and with collimating lens are gained based on light intensity coupling principle analysis. The effect of lens on reflective optical fiber displacement sensor characteristics is analyzed. Then, effect of transmission efficiency and interference on measurement results is evaluated. The static measurement and smog interference experiment of the sensor with and without collimating lens are completed. The results show that the linear measuring range of the sensor designed is 2.6 mm, and the antipollution ability is proved. It provides a reference for the application of reflective optical fiber displacement sensor in gas turbine tip clearance environment.