High power output fiber optic torque sensor with high sensitivity

In order to realize high precision real-time measurement of torque, a high sensitivity torque sensor based on high power output fiber is proposed. The excitation mode, output power, torque sensitivity and other aspects of the sensor are systematically studied. A Single mode-Multimode-Single mode cascade torque sensor is proposed. A cascade single mode-multimode-single mode (SDS) microstructure was fabricated by using a high power output fiber with a core diameter of 135 µm and a cladding diameter of 155 µm instead of the traditional multimode fiber. This kind of fiber can excite more high order modes, which is beneficial to the coupling of multiple modes. When the fiber is twisted, the fiber torque changes, which causes the change of optical path difference in the fiber and makes the interference spectrum drift, so as to realize torque sensing. The experimental results show that the sensitivity of the sensor is 18.907 nm / rad in the rotation angle range of 30° −55 °. The sensor has the advantages of simple design, low price, high sensitivity and strong anti-jamming ability in which case it has strong research value.