(1) Research Center for Nanodevices and Systems, Hiroshima University, 1-4-2 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan
Abstract:
We have developed a novel branched optical waveguide using a stacked directional coupler, which consists of two Si3N4 core layers (each 0.3 μm thick) stacked with a thin (0.2 μm) SiO2 film in between. Using this stacked high-index-contrast system, the size of the multiple branched waveguides can be dramatically reduced compared with the conventional Y-shaped branches. A four-branch optical waveguide is designed and fabricated, and good performance of distribution power of 25 ± 4% to each branch has been achieved.