Patent ID: 9690043
Date: 2017-06-27
CPC Classifications: G02B

Claim:
1. An optical waveguide, comprising: a lower cladding layer, a waveguide core provided on the lower cladding layer; wherein the waveguide core includes a first region, a second region having a step at which a thickness varies, and a third region having a thickness smaller than that of the first region, the second region has thick film regions continuing with the first region and positioned at both sides in a widthwise direction, the thick film regions having a thickness that is equal to that of the first region and having a gradually reducing width from the first region side to the third region side, and has a thin film region sandwiched by the thick film regions and continuing with the third region, the thin film region having a thickness equal to that of the third region, the first region, the second region and the third region of the waveguide core are made from a same material, lower surfaces of the first region, the third region, the thick film regions and the thin film region are contacted with an upper surface of the lower cladding layer, and the cross section perpendicular to a waveguide direction of the thick film regions and the thin film region in the second region is squarish U shaped and opened up.