Demonstration of Large Coupling-Induced Phase Delay in Silicon Directional Cross-Couplers

Journal article (2013)
Department
ImPhys/Imaging Physics (AS) (TU Delft)
Copyright: © 2013 IEEE
DOI: https://doi.org/doi:10.1109/JSTQE.2013.2292874
Integrated optics Silicon-on-insulator technology Optical waveguides Directional couplers Optical devices Optical filters
More Info
expand_more

Published Date

26-11-2013

Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Source:

IEEE Journal of Selected Topics in Quantum Electronics, 20 (4), 2014

ISSN:

1077-260X

Faculty

Applied Sciences

Department

ImPhys/Imaging Physics

Abstract

We investigate directional couplers in silicon-on-insulator photonic technology. We theoretically and experimentally demonstrate a large coupling-induced phase delay that occurs when nearly all light is coupled from one waveguide to the other, i.e., when the coupler operates as a cross-coupler. We show that even a tiny asymmetry in the two waveguides of the coupler causes a significant additional phase delay. The observed change in the free-spectral-range of ring resonators from 5.0 nm to 6.4 nm is explained by a small 0.1% difference in the propagation constants of the two waveguides. Such a difference can be caused by for example a 1 nm difference in the widths of the two waveguides.