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Proceedings Paper

Fiber grating sensor array interrogation with direct-wavelength readout of a wavelength-scanned fiber laser
Author(s): Minho Song
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Paper Abstract

We present a novel interrogation method to measure wavelength shifts in fiber Bragg grating sensor array. A fiber laser tuned by an intracavity FP (Fabry-Perot) filter was used to interrogate Bragg wavelength variations. To solve the linearity, stability, and accuracy problems caused by the nonlinear response of FP filter, we calculated the wavelength variation of the fiber laser using quadrature signal processing with an unbalanced M/Z (Mach-Zehnder) interferometer and time-delayed sampling technique. The phase modulated interferometric signal is sampled with time delay, generating quadrature phase-delayed signals. By applying arctangent demodulation and phase unwrapping algorithm to the signals, accurate wavelength readout is performed. The calculated wavelengths are mapped to corresponding temporal reflection peaks from the sensor array, which enables more accurate fiber grating interrogation without the problems from the FP filter’s nonlinear response. The wavelength resolution of ~ 20 pm was obtained in our experimental setup, which could have been greatly enhanced with faster phase modulation.

Paper Details

Date Published: 21 October 2003
PDF: 8 pages
Proc. SPIE 5206, Photorefractive Fiber and Crystal Devices: Materials, Optical Properties, and Applications IX, (21 October 2003); doi: 10.1117/12.504698
Show Author Affiliations
Minho Song, Chonbuk National Univ. (South Korea)


Published in SPIE Proceedings Vol. 5206:
Photorefractive Fiber and Crystal Devices: Materials, Optical Properties, and Applications IX
Francis T. S. Yu; Ruyan Guo; Shizhuo Yin, Editor(s)

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