FBG based strain sensor with temperature compensation for structural health monitoring

In this paper, we have designed a temperature insensitive strain measurement sensor for structural health monitoring system (stress measurement in Bridge, Buildings, pillars in factory). In some situation, there is a need to measure only the strain but due to some environmental conditions like temperature which creates the interference problem, due to the nature of FBG which is sensitive to both temperature and strain. We have designed and analyzed a sensor based on two FBGs (Fiber Bragg Grating) to eliminate this cross sensitivity which is operated at bandwidth of 0.12 nm to overcome the overlapping of reflected wavelength. The shift in wavelength in individual FBGs is subtracted to each other to extract the shift in wavelength due to desired physical effect.