Because of the characteristic of wavelength encoding, fiber Bragg grating (FBG) has the advantages of immunity to light power fluctuation, variation in polarization and connecting loss, so it has high sensing precision. However, for the demodulation of FBG, wavelength signal is usually converted to electric amplitude signal. By measuring the amplitude signal, the sensing result is obtained. It is well know that the amplitude signal is easy to be disturbed in sense. For this reason, amplitude demodulation limits the effect of wavelength encoding of FBG. This paper presents a novel method of counting wavelength demodulation for FBG sensors using a high birefringent fiber (HBF) loop mirror. This demodulator has simple structure, high precision, low cost and convenient to use. The resolution of the loop mirror device with 30 meter long of HBF is 0.067 nm. This counting wavelength demodulating method has the significance for widespread practical application of FBG sensors.

Date Published: 2 July 2007
PDF: 4 pages
Proc. SPIE 6619, Third European Workshop on Optical Fibre Sensors, 66193L (2 July 2007); doi: 10.1117/12.738646

Published in SPIE Proceedings Vol. 6619:
Third European Workshop on Optical Fibre Sensors
Antonello Cutolo; Brian Culshaw; José Miguel López-Higuera, Editor(s)