Patent ID: 8532452
Filing Date: 2013-09-10
Classification: G02B

Abstract:
1. An optical device comprising a pair of first optical waveguides of a directional coupler, the first optical waveguides being disposed so as to be apart from each other in a horizontal direction, a pair of second optical waveguides connected to the first optical waveguides and guiding light, the second optical waveguides being disposed so as to be apart from each other in the horizontal direction, and a common cladding of the first and second optical waveguides, wherein: the common cladding of the first and second optical waveguides includes a first cladding and a second cladding, the second cladding being provided on the first cladding and having a refractive index that is in a range of 1.46 to 1.8, and that is higher than that of the first cladding and lower than those of the first and second optical waveguides; the first optical waveguides and the second optical waveguides are formed continuously on the first cladding with a constant width and a constant height and are integrated with each other in a light propagation direction, and the constant height is greater than the constant width such that the constant height is about 0.30 μm and the constant width is about 0.29 μm; a cross sectional shape of each of the first and second optical waveguides is a rectangular shape that is longest in a direction orthogonal to a surface of the first cladding; and in a cross-section of both the first optical waveguides and the second optical waveguides, a rear surface thereof is covered with the first cladding, and a side surface and a top surface thereof are covered with the second cladding.