Simultaneous measurement of directional torsion and temperature by using a DC-sampled helical long-period fiber grating

• Published in: Optics and laser technology 2021-10, Vol.142, p.107171, Article 107171
• Main Authors: Zhu, Chengliang, Zhao, Yong, Chen, Maoqing, Tong, Ruijie, Hu, Sheng, Li, Hongpu
• Format: Article
• Language: English
• Subjects: Ambient temperature; CO2-Laser processing platform; Crosstalk; DC-sampled helical long-period fiber grating; Gratings (spectra); Laser processing; Sapphire; Simultaneous measurement of the torsion and temperature
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/j.optlastec.2021.107171

•A fiber-optic sensor for simultaneous measurement of torsion and temperature is demonstrated.•The proposed DC-sampled HLPG can create multiple loss-dips with identical depth and different sensitivities.•Both the torsion amounts and torsion direction can be discerned.•The crosstalk effects between the temperature and the torsion can be well discriminated.•The proposed sensor has competitive sensing sensitivity and low-cost. A new approach based on the utilization of a DC-sampled helical long-period fiber grating (DCSHLPG), enabling the simultaneous measurement of the directional torsion and ambient temperature is proposed and demonstrated. The DCSHLPG is fabricated by specially designed CO2-Laser processing platform which supports both sapphire-tube based fiber twisting and point-by-point grating writing technique. By adopting the proposed method, the crosstalk effects between the temperature and the torsion can be well discriminated, and both the torsion amounts and the torsion direction can be measured simultaneously. Moreover, the proposed sensor has competitive sensing sensitivity and low-cost. Resolutions of the torsion and temperature obtained in this study are estimated to be 0.49°at a torsion angle ranging from −360° to + 360° and 0.08 °C in a temperature ranging from 24 °C to 100 °C, respectively.