A new methodology to characterize mechanical properties of materials using a fiber Bragg grating is reported. A theory for the new technique to measure indentation is developed and experimental results performed by the technique are reported. The measurement range, displacement sensitivity, penetration depth, and forces against the fiber and the sample are analyzed. The load-depth curve of a typical indentation measurement was obtained. The technique has dual sensing abilities for applied force and the corresponding displacement, and it is shown that the method can be used as an instrument to characterize material surfaces. The dynamic measurement, small size sensing, simple measurement configuration, linear responsive, behavior, and easy interpretation are some of the characteristics of this design. (c) 2006 American Vacuum Society.