| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide waveguides crossing each other three-dimensionally, in which waveguide layers different in inter-substrate distance are joined to each other at a low loss, which can be manufactured while widening the manufacturing tolerance thereof, the loss of which is not dependent on the number of channels and in which a low-loss crossing can be realized. <P>SOLUTION: A second waveguide (703) being an add port of the waveguides crossing each other three-dimensionally is characterized in that a double core structure, in which a first core (401) having a tapered structure is involved in a third core (405), and another double structure, in which a second core (403) having the tapered structure is layered on the third core, are arranged so that each tapered tips of the first and second cores are away from each other and opposed to each other; and the tapered tips are connected to each other by the third core. A mode field of the light transmitted through the waveguide of the first core is transformed adiabatically and the transformed mode field is transmitted to the waveguide of the second core through the third core being an intermediate layer. The core of the second waveguide and the core of a first waveguide (701) being a pass through port are made to cross each other above the core of the first waveguide. According to this constitution, an excessive loss (a cross loss) can be decreased remarkably. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
