were measured to be 1.596 nm/°C, as shown in Figure 5, and the output power variations were 2.902 W/°C, as shown in Figure 6.
Bianthrone was studied in great detail in the thermo-chromism and material segment of chemiluminescence, however, bianthrone has rarely been applied to the sensor. A previous report announced that the wavelength responses of optical-fiber sensors were 0.39 nm/°C, 0.65 nm/°C, and 0.71 nm/°C when the waveguide materials were AZ4562, polystyrene, and AZ1512, respectively [10]. The sensitivity results of this report (resonant-wavelength responses: 1.596 nm/°C and output-power variation: 2.902 W/°C) provide excellent data in comparison with those of the previous ones.
4. CONCLUSION
A novel temperature sensor has been manufactured and characterized using evanescent field coupling between the fiber-to-planar waveguide (PWG) coupler and a prism. A newly proposed sensor based on combining a prism and a planar waveguide has been presented as a way to accomplish the improved structure of an existent side-polishing-style optical-fiber sensor. The proposed sensor improves the simultaneous measurement mechanism by employing wavelength-and intensity-based methods at the same time. The response of the resonant wavelength with temperature variations was 1.596 nm/°C, and the output-power variations were measured at 2.902 W/°C. The side-polished fiber sensor manufactured in this study presented the possibility that it can be applied to more accurate and variable sensors by introducing a new mechanism in which the absorption coefficient changes only with a refractive index in a planar waveguide.