Optical waveguide type star coupler

Claim 1

An optical waveguide type star coupler, comprising: a substrate; a light propagating core provided on said substrate, said light propagating core including a plurality of Y-branching waveguides which are connected to each other to provide a waveguide structure with a plurality of stages of dividing signal light in a direction of elongation of the coupler, wherein one of said Y-branching waveguides is connected by a non-branching waveguide path to one of two branching waveguide paths of a Y-branching waveguide of a preceding stage of said waveguide structure and by two branching waveguide paths to respective non-branching waveguide paths of two Y-branching waveguides of a following stage of said waveguide structure; a signal light input port to which a signal light is supplied, said signal light input port being connected to a non-branching waveguide path of the Y-branching waveguide of a first stage of said waveguide structure; at least one exciting light input port to which an exciting light is supplied, said exciting light input port being connected to said non-branching waveguide path of said Y-branching waveguide of said first stage where the signal light is combined with the exciting light; and a plurality of output ports connected to corresponding branching waveguide paths of said Y-branching waveguides of a last stage of said waveguide structure and providing a plurality of equally divided output signal lights; wherein said signal light combined with said exciting light during propagation through said light propagating core is amplified and outputted from said output ports.