Fiber optic liquid level sensor using multimode fused coupler

An intensity based fiber optic liquid level sensor for continuous measurement is described. The sensing principle is based on intensity of reflected light which is disturbed by the change in proximity of the fiber probe and the reflector. A Mechanical CAM is used in the sensing arrangement. It converts the rotatory motion into a linear displacement. As the liquid level raises, rotation of the CAM takes place and the CAM follower connected to it moves linearly. A reflector which is attached to the end of the CAM follower reflect the incident light. As the displacement of reflector occur the intensity of reflected light also changes and is a measure of change in liquid level. The prototype designed sensor can sense liquid level upto 17cm. The proposed sensor can find potential applications in transportation and process industries.