Open AccessAll-fiber seawater salinity sensor based on fiber laser intracavity loss modulation with low detection limit
Author(s) -
Wei Xu,
Yang Xiang,
Chao Zhang,
Jia Shi,
Degang Xu,
Kai Zhong,
Ke Yang,
Xujin Li,
Weiling Fu,
Tiegen Liu,
Jianquan Yao
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.001529
Subject(s) - optics , materials science , fiber optic sensor , optical fiber , multi mode optical fiber , fiber laser , laser , fiber bragg grating , sensitivity (control systems) , physics , electronic engineering , engineering
An all-fiber seawater salinity sensor based on intracavity loss-modulated sensing in a fiber ring laser is proposed and experimentally demonstrated. An optical fiber multimode interferometer, which is based on single-mode-no-core-single-mode fiber structure, is cascaded with a fiber reflector and used as a reflected sensing head to enhance loss-modulated depth. It is inserted in a fiber ring laser and the intracavity loss-modulated salinity sensing is induced for the fiber laser's output intensity. The salinity sensitivity is measured to be 0.1 W/‰ with a high signal-to-noise ratio more than 49 dB and narrow full width at half maximum less than 40 pm. The temperature cross-sensitivity characteristic and stability are also analyzed. Considering the errors from cross-sensitivity, stability and resolution of the photodetector, the detection limit of the sensor system is 0.0023 ‰ (0.0002 S/m), which is comparable to the most advanced commercial electronic salinity sensor.