Method and device for coupling an optical signal from a first light guide into a second light guide

Claim 1

Method for coupling an optical signal from a first light guide into a second light guide, the optical signal being injected through the coating into the cladding and the core of the first light guide, the optical signal from the second light guide being detected through the coating, and the ends of the light guides being aligned in such a way that the largest possible part of the optical signal from the end of the first light guide will be coupled into the end of the second light guide, characterized by a. the radiation of the optical signal at a straight part of the first light guide at an angle of at least 10° and at most 20 0 with regard to the longitudinal axis of the first light guide via a medium the refractive index of which is lower than that of the coating; b. the mounting of a reflective surface on the coating of the first fibre at a part opposite to the plane of irradiation and in a straight line with the axis of the direction of irradiation; c. the conversion of the cladding modi of the optical signal into modi led by the core by bending the first light guide over a bend of at least 45° and at most 180 0 with a radius of curvature of at least 3 mm and at most 10 mm at a distance .of at most 10 mm from the plane of irradiation; d. the alignment of the cores of the first and the second light guides; e. the coupling of the optical signal out of the core of the second light guide via a medium the refractive index of which is higher than that of the coating.