@article{oai:kitami-it.repo.nii.ac.jp:00008266,
 author = {Yasui, Takashi and Tsuji, Yasuhide and Sugisaka, Jun-ichiro and Hirayama, Koichi},
 issue = {23},
 journal = {Journal of Lightwave Technology},
 month = {Dec},
 note = {We extend topology optimization method with function-expansion-based refractive index distribution to optimization for three-dimensional optical circuits, in which a refractive index distribution in a design region is expressed by an expansion with some analytical functions. Three-branch optical waveguides have been optimized as numerical examples. Equally branching three-branch waveguides are achieved using our method. A limitation of topology optimization in two dimensions and dependency of initial structure are also shown.},
 pages = {3765--3770},
 title = {Design of Three-Dimensional Optical Circuit Devices by Using Topology Optimization Method With Function-Expansion-Based Refractive Index Distribution},
 volume = {31},
 year = {2013}
}