High-precision optical fiber sensor system with a novel interrogation system

Abstract

A novel high-precision optical fiber sensor system is proposed and experimentally demonstrated. In order to simultaneously enhance the sensitivity, and detection range of the sensor system, the fiber laser technique, optical heterodyne detection method, and frequency hopping technique are integrated and employed to detect both tiny and unobservable variations over a large measuring range in the sensing values. Besides, to further optimize the sensitivity and stability of the system, a custom-designed RF-Signal Analyzing System (RF-SAS) is used to overcome fiber laser wavelength-vibration effect and extract desired and accurate values from noised-like sensing signals. Experimental results show that when different weights are gradually hung vertically on the FBG sensor to give corresponding strains, the proposed sensing system can simultaneously support high-accurate detection over a wide and extensible detection range. Every 1 mg strain variation can be detected clearly when the strain is increased from 0 mg to 30,000 mg or more.