
The fiber optic sensors are small, electrically isolated and immune to electromagnetic field, they are an correct choice to detect the vibration, cracks on building and environment factors Practically, microbend fiber optic pressure force sensors are limited to intensity-modulated and interferometric (or phase-modulated) methodologies. The main purpose of this project we propose an analyzing of the response of a force pressure optical fiber sensor .The relation between the output power and the applied force pressure show that an optical fiber sensor with these design can covenanting allow the measuring the force/stress applied to a mechanical structure or which it is linked, by optimizing the uses of appropriate materials for constituting the sensor support. In this work ,the transmitted beam power through the optical fiber due to force pressure on optical fiber to determine the pressure sensitivity .A multimode optical fiber (50,125) is pressed by using force in the range (5-50) N at (1) m multimode fiber. The fiber is passed through microbend cell made from Al material at dimension (3.2 7.5) cm.