A shape sensor system includes a deflection sensor comprising an optical fiber having at least one fiber Bragg grating (FBG) written therein and a substrate, the fiber being attached to the substrate with a selected bias distance from a neutral plane of the deflection sensor. The system further includes an optical source coupled to the fiber to provide input light to be at least partially reflected by the FBG, and an optical detection and processing system arranged to receive at least a portion of the output light and to determine a wavelength shift resulting from a change of an amount of deflection of the deflection sensor. The optical detection and processing system determines a relative amount of deflection of the deflection sensor at the FBG based on the wavelength shift. The selected bias distance is selected based on an expected range of deflection angles to be detected.