Title :
A novel fiber torsion sensor using a high-birefringence fiber Bragg grating for demodulation
Author :
Chue, Bo-Rong ; Lo, Yu-Lung
Author_Institution :
Dept. of Mech. Eng., Nat. Cheng Kung Univ., Tainan, Taiwan
Abstract :
A novel high-birefringence (Hi-Bi) fiber torsion sensor demodulated by a Hi-Bi fiber Bragg grating (FBG) is proposed in this study. The characteristics of a twisted Hi-Bi fiber sensor are analyzed by using the Jones matrix. As a result, the ratio of intensities from two reflecting Bragg wavelengths is varied with the twist angle in the measured Hi-Bi fiber. The advantages of the novel torsion sensor are: (1) insensitivity to intensity variations from the light source, (2) insensitivity to the torsion gauge length, (3) insensitivity to the thermal variation and external axial strain, (4) absolute measurement in the twist angle, and (5) multiplexing. Therefore, it could be applicable for smart structure applications, especially in bridges or other civil structures. However, freedom from transverse loading in order to prevent birefringence change in the twisted Hi-Bi fiber is necessary.
Keywords :
Bragg gratings; birefringence; demodulation; distributed sensors; fibre optic sensors; intelligent structures; matrix algebra; torsion; FBG demodulator; Jones matrix; absolute twist angle measurement; bridges; civil structures; external axial strain insensitivity; fiber Bragg grating; high-birefringence fiber torsion sensor; light source intensity variations insensitivity; multiplexing; smart structure applications; thermal variation insensitivity; torsion gauge length insensitivity; Bragg gratings; Demodulation; Fiber gratings; Goniometers; Intelligent sensors; Optical fiber sensors; Sensor phenomena and characterization; Strain measurement; Thermal sensors; Wavelength measurement;
Conference_Titel :
Sensors, 2002. Proceedings of IEEE
Print_ISBN :
0-7803-7454-1
DOI :
10.1109/ICSENS.2002.1037225
