The fact that the wavelength shift in fibre Bragg grating sensors is insensitive to intensity fluctuations has made them superior to other intensity-based and phase-based sensors. However, the intensity variations from the macrobending of the lead-in/out fibres during high frequency disturbances can cause deviations of the signal when a tunable filter scans the Bragg wavelength. In this paper, an optical spectrum analysis method is utilized for characterizing the deviation of the signal caused by the intensity variations in the lead-in/out fibres. It is concluded that the intensity effects from the macrobending of the lead-in/out fibres, which are considered negligible, should be considered in environments with high-frequency disturbance. Therefore, a cancellation method is introduced to compensate for the intensity variations in the lead-in/out fibres in a Bragg grating sensing system. Experimental data on deviations of the signal are in good agreement with the analytical predications and a cancellation technique can be effectively applied to environments with high-frequency disturbance, especially in explosive tests.
All Science Journal Classification (ASJC) codes
- Engineering (miscellaneous)
- Applied Mathematics