| 摘要 |
An optical waveguide directional coupler includes a base having a planar member and a ridge member and an optical waveguide in the base. The ridge member extends from the planar member and has an upper surface where the optical waveguide exposed. The optical waveguide includes a first flat side surface, a second flat side surface parallel to the first flat side surface, a third flat side surface, a fourth flat side surface parallel to the third flat side surface, and a first flat connection side surface. An included angle theta1 between the first and third flat side surfaces is an obtuse angle, an included acute angle alpha1 is formed between the first flat connection side surface and the second flat side surface, and theta1 and alpha1 satisfy alpha1<(180�-theta1). |
