Patent ID: 9279939
Filing Date: 2016-03-08
CPC Classification: G02B

Claim Text:
1. A spot-size converter comprising: a cladding layer having a principal surface defining a plane; a first core layer disposed on the principal surface of the cladding layer, the first core layer having a light input/output portion and a first transition portion having a width W a second core layer disposed on the principal surface of the cladding layer, the second core layer being composed of a material different from a material of the first core layer, the second core layer having a second transition portion extending along a second axis and a propagation portion coupled to the second transition portion, the second transition portion having a width W an over-cladding layer disposed on the principal surface of the cladding layer, and side surfaces and top surfaces of the first and second core layers, wherein the first core layer has a refractive index between a refractive index of the second core layer and a refractive index of the cladding layer, the first core layer and the second core layer are located adjacent to each other and separated from each other by a separation, the plane of the principle surface or a plane parallel to the plane of the principle surface passes through each of the first core layer, the second core layer and the separation, and is substantially perpendicular to a third axis extending in a direction of thickness through the cladding layer, and the first and second core layers, the first transition portion and the second transition portion have a gap therebetween, the first transition portion is optically coupled to the second transition portion, the first core layer has a thickness different from a thickness of the second core layer, the over-cladding layer is disposed in the gap between the first transition portion and the second transition portion, and a ratio (W