Fiber-optic sensor for detecting moisture or measuring temperature, has concave boundary surfaces for coupling reflected light into receiving fiber

摘要

A light transmitting fiber (9) is connected to a light source. A light detector is connected to a light receiving fiber (10). An optically transparent sensor head (13) is connected to the transmitting and receiving fibers and has two concave boundary surfaces (A r, A l) arranged so that light coupled from the first boundary surface, via the transmitting fiber, into the second boundary surface, is reflected on the second boundary surface and emitted into the receiving fiber.