A Large Measurement Range Bending Sensor Based on Microfiber Probe

A large measurement range bending sensor based on a microfiber probe is proposed and experimentally demonstrated. The microfiber probe is simply fabricated by snapping a multimode biconical microfiber in the nonadiabatic tapering process, forming a reflection-type sensing unit. Such probe-type sensor is operated as an in-line Michelson interferometer with compact size. Bending deformation applied on the sensor will affect the refractive index profile of microfiber probe, resulting in the wavelength shift of resonance dip. The experimental results indicate that the microfiber probe-based bending sensor has a large curvature range of 0-11.82m
^-1
. Meanwhile, the maximum curvature sensitivity of 700pm/m
^-1
has been achieved in the range of 8.73-11.82m
^-1
. The microfiber probe-based bending sensor has the excellent advantages of compact size, large curvature range and good flexibility, which is suitable to measure bending deformation in semi-enclosed spaces and provides a great application prospect in wearable sensing devices for human motion monitoring.