A new ultra long-period fiber grating for measuring torsional characteristics

ABSTRACT

In this paper, we proposed a novel kind of periodic helical ultra-long period fiber grating (U-LPFG) for measuring the torsion rate and distinguishing the torsion direction. The sensor was fabricated by spirally deforming a common fiber by local heating for 4 periods. This method of fabrication was not only easy to implement, but also further increased the sensitivity of the grating to the torsion because of the spiral structure. This paper introduced the torsional characteristics of this sensor in detail and drew some relevant conclusions. Experimental results showed that the twist sensitivity of 0.085 nm/(rad/m). Meanwhile, the temperature sensing characteristic of the proposed U-LPFG was also tested as 68 pm/°C within the range of 30 °C ∼210 °C. Therefore, this proposed sensor could achieve good results in simultaneously measuring the torsion rate and distinguishing the torsion direction, and it may have great potential in some practical applications.

KEYWORDS:

• Helical
• long-period fiber grating
• torsion rate
• torsion direction
• simultaneous measurement

Acknowledgements

This work is funded by National Nature Science Foundation of China (Grant nos.: 61377084, 41174161), Joint Research Fund in Astronomy (Grant nos.: U1831115, U1631239) under cooperative agreement between the National Natural Science Foundation of China (NSFC) and Chinese Academy of Sciences (CAS). Opening Project of Key Laboratory of Astronomical Optics & Technology, Nanjing Institute of Astronomical Optics & Technology, Chinese Academy of Sciences (Grant nos.: CAS-KLAOT-KF201501, CAS-KLAOT-KF201605). In part by the Aeronautical Science Foundation of China (grant number: 201608P6003).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work is funded by National Nature Science Foundation of China (Grant nos.: 61377084, 41174161), Joint Research Fund in Astronomy (Grant nos.: U1831115, U1631239) under cooperative agreement between the National Natural Science Foundation of China (NSFC) and Chinese Academy of Sciences (CAS). Opening Project of Key Laboratory of Astronomical Optics & Technology, Nanjing Institute of Astronomical Optics & Technology, Chinese Academy of Sciences (Grant nos.: CAS-KLAOT-KF201501, CAS-KLAOT-KF201605). In part by the Aeronautical Science Foundation of China (grant number 201608P6003).