| 摘要 |
PURPOSE:To shorten the length of an element so that it can be made small in size, by constituting a waveguide so that each waveguide contents in both ends for constituting the element and its interval widens as it approaches the center, and also, each equivalent refractive index increases as the interval of the waveguides widens. CONSTITUTION:On a substrate 7, optical waveguides 8a, 8b are formed, and this optical waveguide 8a or 8b consists of an input use waveguide 9a or 9b, an output use waveguide 10a or 10b, and waveguides 11a, 12a or 11b, 12b which are placed between said waveguides. As he input use waveguides 9a, 9b advance from an input port, an interval between each of them narrows and they contact each other at a contact P. These input use waveguides 9a, 9b are connected to the waveguides 11a, 11b, respectively, and as the waveguides 11a, 11b advance from a contact P1, an interval between each of them widens, and also, each equivalent refractive index difference increases. That is to say, the equivalent refractive index increases together with width of the waveguide, therefore, as it advances from the contact P1, the width of the waveguide 11a is narrowed, and also, the width of the waveguide 11b is widened, therefore, the equivalent refractive index difference increases. |
