Curvature sensor based on structure of Mach-Zehnder interferometer coated with aluminum-doped zinc oxide

This work presents a novel fiber optic Mach-Zehnder interferometer (MZI) sensor that can measure curvature due to its structure. This structure employs a 2-section MZI filter constructed from SMF-28 fiber using the core offset technique. The source in the 1480-1600 nm range shows intermodal energy interference between the core and the cladding and exhibits six spacing notches for sensing applications. The sensibility obtained was of 0.00018 nm/uW when curvature is applied. However, by including a thin film based on Zinc Oxide (ZnO) and another with Aluminum-doped zinc oxide (AZO) in the sensing arrangement, an increase in the sensitivity was detected with a value of 0.00015 nm/uW and 0.00016 nm/uW, respectively. This sensor can be used for applications in various fields, such as environmental monitoring, engineering, and process control.