Hinkov, V.V.Hinkov2022-03-082022-03-081994https://publica.fraunhofer.de/handle/publica/302975The invention relates to an integrated optical sensor for the measurement of the concentration of optically active substances dissolved in a solution, where a strip-shaped monomode optical waveguide runs along the surface of a substrate, light emanating from a light source is injected into one end of the waveguide and is provided with a surface area in which the substance to be measured is brought in contact with the waveguide and with a light receiver to which the measuring light decoupled from the waveguide is fed. The sensor according to the invention, featuring in particular a high measuring sensitivity and selectivity, is characterized by the fact that the substrate in the X section is a lithium niobate crystal and the waveguide is arranged in the Z direction and is manufactured by titanium diffusion, that an electrode is arranged on either side of the waveguide in an area on the surface of the substrate, said electrodes forming an electrode pair to which an electric volt age is a pplied, and that the waveguide is provided with a polarizer in the direction of light propagation downstream of the waveguide area provided with the electrodes. Good results are also achieved using a sensor whose substrate is a lithium niobate crystal in the X or Y directions and the waveguide is arranged in the Y or X directions if the waveguide in the area of the electrode pair..de608621patent1993-4319388