| CPC G02B 6/1228 (2013.01) [G02B 6/125 (2013.01)] | 8 Claims |
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1. An optical waveguide having a straight waveguide and a waveguide bend connected to each other, comprising:
a tapered waveguide bend inserted between the straight waveguide and the waveguide bend, a curvature radius of the tapered waveguide bend being equal to a curvature radius of the waveguide bend,
a straight tapered waveguide inserted between the straight waveguide and the tapered waveguide bend,
wherein:
a waveguide width of the straight tapered waveguide changes continuously from a waveguide width of the straight waveguide to a smaller waveguide width at a connection point between the straight tapered waveguide and the tapered waveguide bend,
a waveguide width of the waveguide bend is larger than the waveguide width of the straight tapered waveguide at the connection point between the straight tapered waveguide and the tapered waveguide bend,
a waveguide width of the tapered waveguide bend changes continuously from the waveguide width of the waveguide bend to the smaller waveguide width,
a waveguide width that maximizes a square of an absolute value of an overlap integral of a normalized electric field distribution of a fundamental propagation mode of the tapered waveguide bend and a normalized electric field distribution of a fundamental propagation mode of the straight tapered waveguide is selected as the smaller waveguide width, and
the tapered waveguide bend and the straight tapered waveguide are connected with an optical axis of the tapered waveguide bend and an optical axis of the straight tapered waveguide being offset such that the square of the absolute value of the overlap integral of the normalized electric field distribution of the fundamental propagation mode of the tapered waveguide bend and the normalized electric field distribution of the fundamental propagation mode of the straight tapered waveguide at the connection point between the straight tapered waveguide and the tapered waveguide bend is maximized.
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