High Sensitivity Hydrogen Sensors Based on Optical Micro/Nanofiber Couplers Working at the Dispersion Turning Point

The safe utilization of hydrogen as a clean fuel and industry material requires the reliable detection of gas leakage. Thus, hydrogen sensors with high sensitivity and fast response are in urgent demand. Optical hydrogen sensors are especially attractive among various hydrogen detection techniques because of their intrinsic safety. Herein, a high-sensitivity hydrogen gas sensor is proposed based on optical micro/nanofiber couplers working at the dispersion turning point. The Pd coatings used were deposited on the waist region by magnetron sputtering. Due to the phase transition of palladium in the presence of hydrogen, intensity changes in the optical transmission of the devices are produced. It is demonstrated that the proposed platform provides high sensitivity, good repeatability, and selectivity, together with a fast response time for hydrogen detection below the explosive concentration. The response and recovery times are ∼20 and ∼28 seconds, respectively. The detected hydrogen concentration range is 0.1-1.5% (in volume). The detection limit of this sensor is below 0.1%.