Abstract: A method of optically coupling one end of an optical fiber to a waveguide formed on a substrate, such that an end portion of the fiber is fitted in a groove formed in the substrate. The groove is formed by forming a beam-shielding mask having a cutout, on the substrate such that the cutout is aligned with a part of the substrate in which the groove is formed, and by irradiating the above-indicated part of the substrate with a high-energy beam. Alternatively, the groove is formed by a cutting tool. An inclined end surface of the groove left uncut by the tool may be irradiated with a high-energy beam, through a beam-shielding mask which has a cutout aligned with the inclined end surface. The end of the optical fiber, which has a flat face or has a coned or hemi-spherical shape, is positioned for optical coupling with a portion of the waveguide which is exposed to the groove.

Abstract: For use in a mobile radio telephone network including radio telephone sets movable in an area divided into a predetermined number of zones, a communication control system includes a searching arrangement (25, 33) for searching one (15') of radio communication devices of the network as a searched communication device that is assigned to a present one of the zones into which a specific one (11') of the radio telephone sets has moved from a previous one of the zones. For operation of the searching arrangement, a communicating arrangement (22, 25, 32) of the system sends a call signal to a specific one of the radio communication devices that is assigned to the previous zone to transmit the call signal to the specific telephone set and receives a response signal transmitted from the specific telephone set if the specific telephone set were in the previous zone.