Fiber Bragg grating (FBG) is produced in the core of a germania-doped fiber with a permanent periodic index modulation by specific techniques. Its intrinsic advantages over conventional fiber optic sensors makes FBG sensor an attractive candidate in smart structures. The center wavelength of the grating is sensitive to longitudinal strain. In this paper, we report our studies on FBG strain sensors. After giving a linear relationship between wavelength and strain, we demonstrate our experiments with FBGs to measure strain of a deformed aluminum cantilever by the use of an optical multichannel analyzer (OMA IV).