Optical-Fiber Microsphere-Based Temperature Sensors with ZnO ALD Coating-Comparative Study

This study presents the microsphere-based fiber-optic sensor with the ZnO Atomic Layer Deposition coating thickness of 100 nm and 200 nm for temperature measurements. Metrological properties of the sensor were investigated over the temperature range from 100 degrees C to 300 degrees C, with a 10 degrees C step. The interferometric signal was used to monitor the integrity of the microsphere and its attachment to the connecting fiber. For the sensor with a 100 nm coating, a spectrum shift of the reflected signal and the optical power of the reflected signal were used to measure temperature, while only the optical power of the reflected signal was used in the sensor with a 200 nm coating. The R-2 coefficient of the discussed sensors indicates a linear fit of over 0.99 to the obtained data. The sensitivity of the sensors, investigated in this study, equals 103.5 nW/degrees C and 19 pm/degrees C or 11.4 nW/degrees C for ZnO thickness of 200 nm and 100 nm, respectively.

Automated summary

This study introduced a microsphere-based fiber-optic sensor with ZnO Atomic Layer Deposition coating thicknesses of 100 nm and 200 nm for temperature measurements. The investigated sensors showed high linearity and sensitivity, with R-2 coefficients exceeding 0.99 and sensitivities of 103.5 nW/degrees C and 19 pm/degrees C or 11.4 nW/degrees C for ZnO thickness of 200 nm and 100 nm, respectively.