Abstract: An integrated optical waveguide circuit includes a substrate; an optical wavelength multiplexer and an optical power splitter formed on a same surface of the substrate. The optical wavelength multiplexer is composed of a first slab optical waveguide, a second slab optical waveguide, a single or a plurality of input optical waveguides connected to the first slab optical waveguide at one end of the first slab optical waveguide, a plurality of arrayed optical waveguides arranged in parallel and having different lengths and connected to the first slab optical waveguide and the second slab optical waveguide, and a plurality of output optical waveguides arranged in parallel and connected to the second slab optical waveguide. The optical power splitter is composed of the second slab optical waveguide, one or more input optical waveguides, and the plurality of output optical waveguides arranged in parallel and connected to the second slab optical waveguide.

Abstract: A UV-A, UV-B discriminating sensor provided with a photochromic compound or photochromic composition as the sensor portion, the photochromic compound or photochromic composition coloring under exposure to UV of wavelength greater than or equal to 280 nm or less than or equal to 400 nm, and wherein at least a portion of the photochromic layer is covered with a layer containing a pigment which absorbs UV of wavelength less than 320 nm, or with a layer containing a pigment which absorbs UV of a wave length greater than or equal to 320 nm but less than or equal to or equal to 400 nm.

Abstract: Optical recording medium includes a substrate, a coloring agent layer formed on the substrate, a light absorber layer formed on the coloring agent layer and a developer layer formed on the light absorber layer. The coloring agent layer is separated from the developer layer by the light absorber layer and the lamination layer composed of these layers has a uniform thickness. The optical recording medium is produced by vacuum depositing a coloring agent, a light absorber and a developer successively on the substrate to form a multi-layer construction, the substrate being capable of transmitting visible light and near infrared light. Alternatively, the optical recording medium contains a plurality of lamination layers mentioned above. The optical recording medium has a high contrast and achieves a high speed multi-color recording.

Abstract: A recording medium suitable for a laser thermal recording is characterized in that a plasma polymerized film of carbon disulfide or an organic monomer containing a metal is used as the recording medium.A method for manufacturing a laser beam-recording medium of this type is characterized by producing an electric discharge in a CS.sub.2 or an organic monomer gas while evaporating a metal such as Te so as to form a plasma polymerized film containing the evaporated metal on a predetermined substrate.