Patent ID: 7286741
Filing Date: 2007-10-23
Classification: G02B

Abstract:
1. A silica optical waveguide comprising: a silica substrate; a lower clad layer formed on the silica substrate; a first core and an adjoining core that adjoins the first core formed on the lower clad layer; and an upper clad layer formed on the lower clad layer so as to embed the first core and the adjoining core and so as to form a gentle slope on a top surface of the upper clad layer between a position substantially above the first core to a position substantially in a middle of the first core and the adjoining core, wherein the top surface of the upper clad layer has a difference of height in a direction normal to the surface of the substrate between a position substantially above the first core to a position substantially in the middle of the first core and the adjoining core that is not less than about 0.2 μm and that is less than the height of the core.