A sensor for measuring a physical parameter at a first location which is remote from a second location. The sensor has a plurality of light transmitting fibers each having an input end for receiving light from a source and an output end for emitting the received light to a light detector and a lens for focusing light from the source on one of the input ends of the light transmitting fibers. The lens is displaced to project light to a specific one of the input ends of the fibers in accordance with the value of the physical parameter to be measured.