OPTICAL COUPLING APPARATUS FOR COUPLING LIGHT INTO A WAVEGUIDE

摘要

A photocoupler having a polarization converting device (3L) for converting a laser light emitted from a laser source (1) to a polarized light (6B) having an electric vector oriented in a direction of a tangent of a circle having its center on an optical axis of the photocoupler and the phase of which is shifted by pi at the boundary of a disclination line passing the center of the circle and the wave front of the converted laser light (6B) is spherical and a coupler (5) for exciting a waveguided light (7) which propagates from the center (0) thereof radially wherein said coupler (5) is positioned so that the input coupling efficiency becomes maximum.