Abstract: The present invention relates to a multichannel optical path changing device that is constituted of resin optical waveguides and mirrors and that changes a direction of an optical path. This device has monolithically formed cores having a mirror therebetween and optical path directions changed, and has multichannel cores simultaneously formed under a condition that their positional relationship is maintained. This device can be produced by a first or second method. The first method comprises steps of forming a parallelepiped block on a substrate by a cladding resin; forming a film of a core layer to cover the block by a core resin; and simultaneously forming cores having an optical path direction rectangularly changed, by selectively etching the core layer and the block.

Abstract: The present invention relates to a multichannel optical path changing device that is constituted of resin optical waveguides and mirrors and that changes a direction of an optical path. This device has monolithically formed cores having a mirror therebetween and optical path directions changed, and has multichannel cores simultaneously formed under a condition that their positional relationship is maintained. This device can be produced by a first or second method. The first method comprises steps of forming a parallelepiped block on a substrate by a cladding resin; forming a film of a core layer to cover the block by a core resin; and simultaneously forming cores having an optical path direction rectangularly changed, by selectively etching the core layer and the block.

Abstract: A nonexplosive chemical composition for gently and noiselessly breaking a rock or concrete mass. The composition comprises a principal component which is prepared by calcining a starting mixture comprising 100 parts by weight of quick lime and 1-20 parts by weight of calcium fluoride. In rock or concrete breaking operations, this composition in the form of aqueous slurry is poured into drill-holes and left to spontaneously hydrate and set with development of expansion pressure. For adequate retardation of the hydration, preferably a second fluoride such as Na.sub.2 SiF.sub.6 which gives CaF.sub.2 by reaction with CaO at the calcination temperature is added to the starting mixture. As an alternatively preferable method for the same purpose, an amino acid compound and/or a lignosulfonate is used as a hydration retarding agent which is mixed with the calcined principal component. Various auxiliary agents may optionally be added to this composition.