OPTICAL DEVICE FOR OPTICAL COMMUNICATION

摘要

PURPOSE: To eliminate a laser beam returning to a laser beam source side by reflection in the non-effective region of a reflection mirror and to enable optical communication with high accuracy by adequately constituting the non-effective region when a reflection system is used in a part of a laser beam projecting system. CONSTITUTION: A laser beam flux A is condensed at a point 3 by a refractive system 2 installed in the aperture of a main mirror 5 and is then made incident as a divergent beam on a sub-mirror 4. This sub-mirror 4 is provided with an aperture of approximately the same size in the non-effective region 4c of a circular shape inclusive of its optical axis Sa. The non-effective region 4c is provided with a so-called black body absorbing part 4b as an adjusting member. The black body absorbing part 4b is formed to a shape bent at the front end of a conical cylinder. The inside wall thereof consists of a black material which absorbs light and is so constituted that the incident light is reflected plural times on the inside surface and is successively absorbed to substantially prevent the release of the light outside. As a result, the generation of the recurrent luminous flux C resulted by incidence of the circular luminous flux inclusive of the optical axis on the inner side of the luminous flux B on the non-effective region 4c of the sub-mirror 4 and the return thereof to the laser oscillator side by reflection is prevented.