Early detection of decalcification is vital in osteoporosis diagnosis and treatment. Since calcium ions are the main factor in bone strength, decalcification degrees in bone can be classified through assessment of the variation in its mechanical response to applied load. In this paper, an innovative non-radiation, low cost method is proposed for assessment of bone decalcification which is capable of discrimination of low grade decalcification. This capability is due to employment of high resolution fiber optic sensor (FOS) with the strain sensitivity of 27.8 pm mu epsilon(-1) that detects the decalcification through measurement of strain induced by loading. The sensor design procedure is based on genetic algorithm. By the means of mode field diameter (MFD) variation as a sensor indirect parameter, the common problems of intensity modulated optical sensors are overcome. Moreover, the sensor operation is nearly independent of temperature variation and the compensation requirement is removed. (C) 2017 Elsevier Ltd. All rights reserved.