A highly sensitive torsion sensor based on symmetrically polished SMS fiber structure.

We propose and experimentally demonstrate an optical fiber torsion sensor based on symmetrically polished single-multi-single mode (SP-SMS) fiber structure. The polished structure enhances the torsion response effectively, which is fabricated by a high-frequency CO 2 laser. Experimental results show that the high sensitivity of the proposed torsion sensor reaches 1.032 nm/(rad m−1) in the range from − 10.261 rad/m to 10.261 rad/m. Meanwhile, the temperature response of the sensor is also investigated, which is 21 pm/°C in the range from 30 °C to 150 °C. Moreover, the structure has the features of low cost, simple fabricating method and small temperature crosstalk. Schematic diagram of the symmetrically polished SMS fiber structure (SP-SMS). The geometrical shape of the sensor is prepared by a high-frequency CO 2 laser, which enhances the torsion sensitivity of the structure. The structure achieves a high sensitivity of 1.032 nm/(rad m−1). Meanwhile, small temperature-torsion crosstalk of 0.03 (rad m−1)/°C is achieved. The fabricating method of the structure has the advantages of is non-contact and scalable. Hence, the proposed structure provides a new idea to the design of the fiber torsion sensor. [Display omitted] • The highest torsion sensitivity of the SP-SMS reaches to 1.032 nm/(rad m−1). • The low temperature-torsion crosstalk is obtained, which is 0.03 (rad m−1)/°C. • Low cost, compact structure and easy fabrication. [ABSTRACT FROM AUTHOR]