Analysis of mode size transformation with a tapered directional coupler.
A simple tapered directional coupler with a five-layered structure is employed for mode conversion between a single-order and higher-order modes. We investigate coupling from higher-order modes to a single-order field theoretically and experimentally. As a result, we confirm that the first two modes in the tapered waveguide are coupled with a single-order mode in another waveguide by computer simulation using the beam propagation method. Furthermore, we fabricated the actual device and observed the streak patterns of the first three modes.
Komatsugawa
H
H
Faculty of Photonics Science, Chitose Institute of Science and Technology, 758-65 Bibi, Chitose, Hokkaido 066-8655, Japan. hiroshi@mail.chitose.ac.jp
Kamata
M
M
Sasaki
K
K