A combined interrogation and signal processing technique which facilitates high-speed simultaneous static and dynamic strain demodulation of multiplexed ﬁber Bragg grating sensors is described. The scheme integrates passive, interferometric wavelength-demodulation and fast optical switching between wavelength division multiplexer channels with signal extraction via a software lock-in ampliﬁer and fast Fourier transform. Static and dynamic strain measurements with noise ﬂoors of 1 nanostrain and 10 nanostrain/sqrt(Hz), between 5 mHz and 2 kHz were obtained. An inverse analysis applied to a cantilever beam set up was used to characterise and verify strain measurements using ﬁnite element modeling. By providing distributed measurements of both ultahigh-resolution static and dynamic strain, the proposed scheme will facilitate advanced structural health monitoring.
- fiber Bragg gratings
- optical fiber sensors
- structural health monitoring
Perry, M., Orr, P., Niewczas, P., & Johnston, M. (2012). Nanoscale resolution interrogation scheme for simultaneous static and dynamic fiber Bragg grating strain sensing. Journal of Lightwave Technology, 30(20), 3252 - 3258. https://doi.org/10.1109/JLT.2012.2213891