Linear FBG interrogation with a wavelength-swept fiber laser and a volume phase grating spectrometer

TLDR: In this article, a novel FBG (fiber Bragg grating) sensor system that uses a tunable wavelength laser and a volume phase grating spectrometer was proposed.

Abstract: We propose a novel FBG (fiber Bragg grating) sensor system that uses a tunable wavelength laser and a volume phase grating spectrometer. The effect of nonlinear wavelength scanning and uneven power profile of the fiber laser, which substantially degrades the measurement accuracy, is minimized by using a spectrometer demodulation. The constructed sensor system showed linear output according to the Bragg wavelength variation, and showed much higher signal-to-noise ratio compared to the conventional spectrometer demodulation which used much dimmer broadband light sources.