Research on Mach-Zehnder interference sensors based on the fused tapered optical fiber technology

This study is based on the principle of inter-mode interference for single-mode optical fiber. Two Mach-Zehnder interference sensors were manufactured by the fused tapered techniques of forward direction with butane torch and reverse direction with fiber fusion splicer, respectively. The temperature sensing characteristic of reverse fused tapered Mach-Zehnder interference sensor is 0.067 nm/°C. And the interference trough moves towards the long wave direction with increasing temperature. However, the temperature sensing characteristic of forward fused tapered Mach-Zehnder interference sensor is 1.059 nm/°C. And the interference trough moves towards the short wave direction with increasing temperature. The results show that, the Mach-Zehnder interference sensors could be flexibly manufactured by the fused tapered technique for different needs such as sensitivity and size. And this study has a high reference value for the practical study of optical fiber sensing.