Patent ID: 7046880

Claim:
An optical coupling element for optically coupling an optical element formed on a substrate to an external optical element disposed adjacent to the substrate, comprising: a first optical waveguide formed on the substrate and having a width on a side of the external optical element smaller than a width on a side of the optical element, the width of the first optical waveguide being tapered toward the side of the external optical element in a first degree; and a second optical waveguide formed on the substrate and connected to the first optical waveguide on the side of the external optical element, and having a width on a side of the external optical element less than half of a width on a side of the optical element, and having a shorter length than a length corresponding to 20 wavelengths of an optical signal, the width of the second optical waveguide being tapered toward the side of the external optical element in a second degree, steeper than the first degree.