Search

Highlights • An optical fiber Mach-Zehnder interferometer has been proposed. • The RI and temperature can be measured without the cross-sensitivity. • The sensitivities are −18.1764 nm/RIU and 0.0733 nm/°C, respectively. • The advantages of cost effectiveness, robustness and easy fabrication. Abstract A Mach-Zehnder interferometer based on single-mode-multimode-thin-core-single-mode fiber structure is proposed and experimentally demonstrated for measuring refractive index and temperature simultaneously. The transmission dips of the sensor will shift when the ambient refractive index and temperature change, so it is possible to measure the refractive index and temperature by monitoring the wavelength shifts of the two transmission dips due to different interference orders. The experimental results show that the sensing sensitivities of refractive index and temperature are −18.1764 nm/RIU and 0.0733 nm/°C within the refractive index range from1.3105 to 1.3517 and the temperature range from 25 °C to 50 °C, respectively. Its cost effectiveness, robustness and easy fabrication will have attractive potential applications in chemical and biological sensing. [ABSTRACT FROM AUTHOR]

An in-line fiber sensor for simultaneous measurement of refractive index (RI) and temperature is proposed and demonstrated. The sensor head is composed of an asymmetric Mach–Zehnder interferometer (MZI), which is combining the single mode-multimode-single mode (SMS) fiber structure and a peanut-shape structure. The transmission dips of the sensor will shift as the ambient RI or temperature variation due to the phase changing. The different wavelength transmission dips formed by the cladding modes interfering with the core mode have different sensitivity responses, so the simultaneous measurement of the RI and temperature can be achieved by monitoring the wavelength shifts of the two transmission dips. The experimental results show that the sensing sensitivities of RI and temperature are −86.7434 nm/RIU and 0.0590 nm/°C in the RI range from 1.3105 to 1.3517 and temperature range from 25 °C to 85 °C, respectively. The novel sensor processes easy fabrication, low cost, and high sensitivity, making it offers high potential applications in physical, biological and chemical sensing. [ABSTRACT FROM AUTHOR]