A Macrobending Fiber Based Micro-Displacement Sensor

An all-fiber micron displacement sensor with a simple configuration is proposed and investigated experimentally. The proposed fiber displacement sensor consists of a half-loop structure of bare high-bend loss singlemode fiber-1060XP, employing the well-known Whispering Gallery mode (WGM) effect. 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 system, a change in displacement can be measured assuming the ratiometric system is calibrated. The proposed macrobending fiber based displacement sensor achieves a higher resolution (less than 75 nm of displacement) than other conventional fiber-optic sensors and also benefits from simplicity.