Highly Integrated All-Fiber FP/FBG Sensor for Accurate Measurement of Strain under High Temperature

• Main Authors: Tingting Yang, Xiu He, Zengling Ran, Zhendong Xie, Yunjiang Rao, Xueguang Qiao, Zhengxi He, Peng He
• Format: Article
• Language: English
• Published: MDPI AG 2018-10-01
• Series: Materials
• Subjects: optical fiber sensors; strain/pressure sensing; Fabry–Perot; FBG; dual-parameter measurement; high temperature
• Online Access: http://www.mdpi.com/1996-1944/11/10/1867

Accurate measurement of strain is one of the most important issues for high temperature environments. We present a highly integrated all-fiber sensor to achieve precise measurements of strain/high-pressure, which consists of a fiber Bragg grating (FBG) inscribed by an 800 nm femtosecond laser cascaded with a micro extrinsic Fabry–Perot (FP) cavity fabricated by the 157 nm laser micromachining technique. FBG is sensitive to temperature, but insensitive to strain/pressure, whereas the FP is sensitive to strain/pressure, but has a small dependence on temperature. Therefore, such a cascaded sensor could be used for dual-parameter measurement and can work well at high temperatures. Experimental results indicate that this device exhibits a good strain characteristic at high temperatures and excellent high-pressure performance at room temperature. Due to its highly sensitive wavelength response, the proposed sensor will have remarkable potential applications in dual parameter sensing in harsh environments.