| Title |
A Study on the Effect of Pressure Sensitivity on the Length of Taper Section in Tapered Polarization Maintaining Fiber |
| Authors |
Sungwook Choi ; Yong Wook Lee |
| DOI |
http://doi.org/10.5207/JIEIE.2020.34.4.001 |
| Keywords |
Optical Fiber Sesnor; Pressure Sensor; Pmf; Sagnac Polarization Loop |
| Abstract |
In this paper, we propose a temperature-independent polarimetric optical fiber pressure sensor (OFPS) using a polarization Sagnac loop composed of a polarization beam splitter, wave plate combination , and a sensor head. The sensor head consists of 10-cm-long tapered panda-type polarization-maintaining fiber (PMF) and a fiber Bragg grating (FBG) directly spliced with PMF, and the sensor head is located inside a pressure chamber. The tapered section length was varied to 0, 200, 300, and 400μm to investigate the dependence of the pressure sensitivity on tapered section length. A pressure-induced birefringence change of PMF results in a wavelength shift of the interference spectrum. Since the PMF has a cross sensitivity to temperature, the FBG is utilized for the compensation of the temperature effect on it. The FBG, which is sensitive to an ambient temperature change but nearly insensitive to a pressure change, was utilized to compensate for the temperature cross sensitivity of the tapered HBF. From the investigation, the pressure sensitivity of the tapered PMF was found out to be proportional to the tapered length. In consequence, the maximum pressure sensitivity of approximately -22.92nm/MPa could be obtained using tapered PMF with tapered section length of 400μm. Its adjusted R2 value representing the sensor linearity was measured as ～0.9887 in an applied pressure measurement range of 0∼0.5MPa. |