Patent ID: 8744225

Claim:
An optical coupling device comprising: a first clad layer having a first surface; a main waveguide having a strip form and including a linearly extending portion and a tapered portion, which is formed on the first surface to extend along a wave-guiding direction of a light wave, wherein the linearly extending portion has an emission port at one end of an emission side from which the light wave is emitted, and the tapered portion has one and other ends, the one end being connected to the other end of the linearly extending portion, the tapered portion has a first width which is gradually reduced towards the other end corresponding to an incident side of the light wave; a plurality of auxiliary waveguides which are formed on the first surface to extend along the wave-guiding direction of the light wave and are arranged in substantially parallel on the both sides of the main waveguide, wherein each of the auxiliary waveguides has first and second tapered portions which are coupled to each other at a coupling side, and the auxiliary waveguides have second widths which are gradually reduced towards the incident side of light wave and the emission side of light wave, from the coupling side, respectively; and a second clad layer which is so formed as to cover the main waveguide, auxiliary waveguides and first clad layer, wherein the first clad layer guides the light wave introduced into the first clad layer or the second clad layer and gradually converge the light wave towards the main waveguide.