Open AccessAll-dielectric unidirectional dual-grating output coupler
Author(s) -
Andrew Greenwell,
Sakoolkan Boonruang,
M. G. Moharam
Publication year - 2007
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.15.000266
Subject(s) - grating , optics , blazed grating , materials science , diffraction grating , dielectric , diffraction , fabrication , diffraction efficiency , substrate (aquarium) , ultrasonic grating , phase (matter) , optoelectronics , physics , medicine , oceanography , alternative medicine , pathology , quantum mechanics , geology
A novel concept for an all-dielectric unidirectional output double-grating coupler is proposed and rigorously analyzed. In addition to a superstrate side grating, a second grating is placed on the substrate side. The periodicities of the gratings are chosen such that no propagating diffracted orders are present outside the structure in the superstrate region and only a single order is present outside the structure in the substrate region. The concept provides a robust output coupler requiring neither phase-matching between gratings nor any resonances in the structure, and is very tolerant to potential fabrication errors. Up to 96% coupling efficiency from the substrate-side grating is obtained over a wide range of grating properties.