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 −35.3 nm/m−1from 1.35 to 2.20 m−1was obtained and high mechanical strength was demonstrated. The temperature–curvature cross-sensitivity of 4.44 × 10−4 m−1/°C was lower than the curvature resolution. The high curvature sensitivity and low temperature cross-sensitivity make this sensor a candidate for practical applications. [ABSTRACT FROM PUBLISHER]