Glycerol–Water Solution-Assisted Mach–Zehnder Temperature Sensor in Specialty Fiber with Two Cores and One Channel

• Main Authors: Haiming Qiu, Chunyu Zhao, Xuehao Hu, Haijin Chen, Qianqing Yu, Zhenggang Lian, Hang Qu
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Photonics
• Subjects: fiber optics sensors; dual-core fiber; interferometer; temperature sensing
• Online Access: https://www.mdpi.com/2304-6732/8/4/103

In this paper, we propose an in-fiber Mach–Zehnder temperature sensor based on a dual-core fiber with an eccentric core and a central core. The latter one is beside a fluidic channel embedded in the fiber. The effective refractive index of the guided mode in the central core could be influenced by the glycerol–water solution filled in the fluidic channel. Thus, the transmitted spectrum of the sensor is shifted as a function of temperature. By monitoring the selected spectral dip shifts, an experimental sensitivity of 2.77 nm/°C is obtained in the range of 25 to 40 °C for a solution length of 15 cm. To further improve the temperature sensitivity, the solution length is increased up to 29.5 cm, and a higher sensitivity of 5.69 nm/°C is achieved in the same temperature range. The experimental results agree well with the theoretical ones. The proposed sensor has good robustness and stability, which makes it promising for applications of high precision temperature monitoring.