Structural Strain and Temperature Measurements Using Fiber Bragg Grating Sensors
Wei Jin*, T.K.Y. Lee, S.L. Ho and H.L. Ho, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong
K.T. Lau, L.M. Zhou and Y. Zhou, Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hong Kong
Fibre Bragg grating (FBG) sensors have been the subject of intense research and development since the discovery of photosensitivity in optical fibers by Hill et al. . An FBG is formed within the core of an optical fiber by introducing periodic variation in its refractive index profiles. The resonance (or Bragg) wavelength (λ B) of the FBG is 
where Λ is the periodicity ...