Abstract: A radiation transmission fiber for spectroscopic monitoring includes a transmission portion and a sensor portion; the transmission and sensor portions have a continuous core portion and continuous cladding over the core portion throughout the transmission and sensor portions; the sensor portion of the core is of smaller diameter than the transmission portion(s) and is connected to the transmission portion(s) by a conical transition portion(s); and the cladding in the transmission portion is of greater thickness than the cladding in the sensor region.

Abstract: An evanescent wave liquid level sensor for measuring the density-compensated level of a liquid in a container. The sensor employs an eccentric core optical fiber fully immersed in the liquid to be measured. Light is injected into one end of the fiber. Some of the light will be lost due to evanescent wave losses. Changes in the ratio of the intensity of the input light and the reflected light are due solely to changes in the density of the liquid. Changes in the liquid density can then be used to compensate a liquid level measurement. Since the liquid temperature is related to its density, the sensor can also be used to measure changes in the liquid temperature.

Abstract: An optical sensor for converting a physical value into an electric output signal comprises a light source from which a beam of light rays is coupled into a first surface of a photoconductive body. The light rays are totally reflected by one boundary surface of, or coupled out from said body in response to a given physical value. The totally reflected light rays impinge upon a second face. A plurality of light-sensitive elements is provided for detecting the angular range .beta. covered by the beam after it has been totally reflected or coupled out, respectively. In order to enable the sensor to be adapted to a plurality of applications and in order to obtain reproducible, digitized output values, independently of any local disturbing factors or long-term phenomena, the body is designed as an elongated waveguide in which light rays are subjected to multiple total reflection. The light-sensitive elements are arranged at an axial distance h from a waveguide face.