| Title |
Study on Optical Fiber Sensor Capable of Discriminating Strain and Temperature using Fiber Transmission Grating Based on High Birefringence Photonic Crystal Fiber |
| Authors |
Sungwook Choi ; Do Kyung Kim ; Yong Wook Lee |
| DOI |
http://dx.doi.org/10.5207/JIEIE.2019.33.9.001 |
| Keywords |
Optical Fiber Sensor; Strain; Temperature; High Birefringence Photonic Crystal Fiber; Fiber Transmission Grating |
| Abstract |
In this paper, we propose an optical fiber sensor capable of separately measuring strain and temperature by incorporating a fiber transmission grating (FTG) based on high birefringence photonic crystal fiber (HBPCF). Since the FTG written on HBPCF (referred to as the HBPC-FTG) has different effective refractive indices according to the principle axis of HBPCF, its resonance wavelength also depends on input polarization. When orthogonally polarized light passes through the HBPC-FTG used as a sensor head, therefore, its transmission spectrum has two clearly different resonance dips (referred to as Dips 1 and 2). They are obtained at one and the other of two orthogonal input polarization. The measured strain sensitivities of these dips are -0.83pm/με for Dip 1 and -1.43pm/με for Dip 2 in applied strain range from 0 to 1960με, and the temperature sensitivities are measured as 8.0pm/℃ at Dip 1 and 4.8pm/℃ at Dip 2 in applied temperature range from 30 to 80℃. Since the strain and temperature responses of the two dips of the HBPC-FTG are highly linear and uncorrelated, the proposed sensor can discriminate strain and temperature changes simultaneously applied to the sensor head by using a simple sensitivity coefficient matrix. |