| Title |
Fiber-optic Torsion Sensor using Long-period Fiber Grating Inscribed on Polarization-maintaining Photonic Crystal Fiber |
| Authors |
Jinsil Han ; Yong Wook Lee |
| DOI |
http://doi.org/10.5207/JIEIE.2020.34.2.027 |
| Keywords |
Fiber-Optic Torsion Sensor; Twist Direction Discrimination; Polarization-Maintaining Photonic Crystal Fiber; Long-Period Fiber Grating |
| Abstract |
In this paper, we demonstrated a fiber-optic torsion sensor capable of discriminating twist direction using a long-period fiber grating(LPFG) inscribed on polarization-maintaining photonic cystal fiber(PMPCF) by CO2 laser pulses. The LPFG written on PMPCF, referred to as the PMPC-LPFG, has a polarization-dependent resonance dip, and two resonance dips are obtained for orthogonal input polarization states designated here as linear horizontal polarization(LHP) and linear vertical polarization(LVP). The torsion responses of these two resonance dips were investigated in a twist angle range from -160° to 160°. When the transmittance of the fabricated PMPC-LPFG, measured on a logarithmic scale, was converted to the transmittance represented on a linear scale, the torsion responses of both dips showed high linearity with an adjusted R2 value greater than 0.99596 in a twist angle range from -160° to 160°. In addition, the temperature response was also examined in a temperature range from 40 to 80℃. The experimental results show that our PMPC-LPFG-based torsion sensor can distinguish torsion direction with excellent linearity and can also offer temperature-insensitive torsion measurement. |