A system measures the strain of an object. The system includes a laser source for generating an output radiation, a strainable optical fiber having first and second facets, and means for calculating a measure of a strain of the optical fiber. The first facet is coupled to the laser source for receiving the output radiation and for transmitting therefrom a guided radiation over the optical fiber towards the second facet. The second facet is adapted to receive the guided radiation and to reflect a corresponding reflected radiation towards the first facet. The laser source is a self-mixing type adapted to receive at least part of the reflected radiation and to mix the output radiation with the received radiation. The calculating means calculate the measure of the strain of the optical fiber through the linear displacement of the second section measured by the self-mixing effect in the laser source.