A linear photodiode array spectrometer based, high resolution interrogation technique for fiber Bragg grating sensors is demonstrated. Spline interpolation and Polynomial Approximation Algorithm (PAA) are applied to the data points acquired by the spectrometer to improve the original PAA based interrogation method. Thereby fewer pixels are required to achieve the same resolution as original. Theoretical analysis indicates that if the FWHM of a FBG covers more than 3 pixels, the resolution of central wavelength shift will arrive at less than 1 pm. While the number of pixels increases to 6, the nominal resolution will decrease to 0.001 pm. Experimental result shows that Bragg wavelength resolution of ~1 pm is obtained for a FBG with FWHM of ~0.2 nm using a spectrometer with a pixel resolution of ~70 pm.

Date Published: 5 March 2007
PDF: 6 pages
Proc. SPIE 6595, Fundamental Problems of Optoelectronics and Microelectronics III, 65952C (5 March 2007); doi: 10.1117/12.726465

Published in SPIE Proceedings Vol. 6595:
Fundamental Problems of Optoelectronics and Microelectronics III
Yuri N. Kulchin; Jinping Ou; Oleg B. Vitrik; Zhi Zhou, Editor(s)