Open AccessEvaluation of slot-to-slot coupling between dielectric slot waveguides and metal-insulator-metal slot waveguides
Author(s) -
Degui Kong,
Makoto Tsubokawa
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.019082
Subject(s) - waveguide , materials science , optics , coupling (piping) , slot waveguide , dielectric , slot antenna , wideband , wavelength , slab , optoelectronics , physics , photonics , silicon photonics , telecommunications , radiation pattern , antenna (radio) , geophysics , computer science , metallurgy
We numerically analyzed the power-coupling characteristics between a high-index-contrast dielectric slot waveguide and a metal-insulator-metal (MIM) plasmonic slot waveguide as functions of structural parameters. Couplings due mainly to the transfer of evanescent components in two waveguides generated high transmission efficiencies of 62% when the slot widths of the two waveguides were the same and 73% when the waveguides were optimized by slightly different widths. The maximum transmission efficiency in the slot-to-slot coupling was about 10% higher than that in the coupling between a normal slab waveguide and an MIM waveguide. Large alignment tolerance of the slot-to-slot coupling was also proved. Moreover, a small gap inserted into the interface between two waveguides effectively enhances the transmission efficiency, as in the case of couplings between a normal slab waveguide and an MIM waveguide. In addition, couplings with very wideband transmissions over a wavelength region of a few hundred nanometers were validated.