Highly sensitive curvature sensor based on an asymmetrical Mach-Zehnder interferometer

Mach-Zehnder interferometers have attracted attention due to their flexible structures and extensive applications. In this study, a simple and highly sensitive curvature sensor based on an asymmetrical Mach-Zehnder interferometer comprising an up-taper and a peanut-like section was theoretically and experimentally characterized. A simulation was conducted to investigate the influence of structural parameters on the interference spectrum. Experimental measurements show that a high curvature sensitivity of -35.3nm/m(-1) from 1.35 to 2.20m(-1) was obtained and high mechanical strength was demonstrated. The temperature-curvature cross-sensitivity of 4.44x10(-4)m(-1)/degrees C was lower than the curvature resolution. The high curvature sensitivity and low temperature cross-sensitivity make this sensor a candidate for practical applications.