Efficient coupling into slow-light one-dimensional fishbone waveguide by mode converter method. (14th June 2017)

• Record Type: Journal Article
• Authors: Zhao, Xiangjie; Dalir, Hamed; Xu, Xiaochuan; Chen, Ray T.
• Is Part Of: Applied physics express. Volume 10:Number 7(2017)
• Publication Date: 2017-06-14
• Subjects: Physics -- Periodicals; Technology -- Periodicals; 621.05
• DOI: 10.7567/APEX.10.072502
• Languages: English
• ISSNs: 1882-0778

Abstract

Abstract: The high-order mode in a fishbone waveguide accommodates the easy manipulation of group index dispersion. To minimize Fresnel reflection, group velocity mismatch can be compensated for by a casual step taper, but with low coupling efficiency. Here, we propose a mode converter to boost the coupling efficiency to in and out of the slow-light fishbone waveguide. Split, phase, and side slots in a mode converter are employed to compensate for the mode mismatch in terms of the width of the lobes, the phase offset, and the power ratio between neighboring lobes. A high coupling efficiency of ∼70% leads to the efficient compact true-time delay required for phased array antennas.