A bend loss-based singlemode fiber microdisplacement sensor

An all-fiber displacement sensor with a simple configuration is proposed and investigated theoretically and experimentally. The proposed fiber displacement sensor consists of a half-loop structure of high-bend loss singlemode fiber-1060XP. A ratiometric power measurement system for interrogating the proposed sensor is also presented. By measuring the change in ratio of bend loss in the ratiometric measurement system, a change in displacement can bemeasured assuming the ratiometric system is calibrated. The proposed macrobending fiber-based displacement sensor achieves a competitive resolution of circa 0.3 lm and also benefits from simplicity compared with conventional fiber Bragg grating-based displacement sensor. The displacement sensor is sensitive to temperature and an experimental investigation of this sensitivity is presented. It is found that the ratio response has a linear variation with temperature; therefore, temperature dependence can be mitigated by a suitable correction process.