Abstract: A novel fiber-optic temperature sensing scheme based on the Mach-Zehnder interferometer (MZI) is proposed to overcome the interference limitation caused by moiré fringes in conventional interferometric measurements, achieving higher measurement accuracy. The scheme constructs a vernier structure in which interference fringes serve as the primary scale and moiré fringes as the secondary scale, transforming moiré fringes from a source of interference into a tool for enhancing measurement precision. Experimental results show that the designed sensor achieves a linearity of 0.911 (R2) and a minimum temperature resolution of 0.03 ℃, with a fourfold improvement in measurement accuracy compared to traditional single-count interferometers. With its intuitive principle and ease of implementation, this approach holds promise as an ideal platform for educational demonstrations, helping students gain deeper insights into interference principles and the vernier effect while fostering research interest.

Key words: Mach-Zehnder interferometer, fiber-optic temperature sensor, Vernier effect, moiré fringes, digital image processing technology