Performance Demonstration of Ammonia Sensor Based on Cascaded-Splice PCF

In this article, a compact gas sensing unit has been proposed and experimentally demonstrated based on photonics crystal fiber (PCF). The fast gas exchange was obtained by an open cavity and the efficient optical coupling with the cascaded-spliced structure. The fusion parameters have been optimized based on the research on their depending relationship with the optical characteristics and sensing performance of the sensing unit. The sensing performance for ammonia has been experimentally verified with the sensitivities of 0.00253 and 0.0007 dB/ppm, respectively, in the concentration ranges of 10–50 and 100–500 ppm. Other performance has also been demonstrated for the response time, stability, repeatability, and selectivity.