Open AccessPhotonic molecules: tailoring the coupling strength and sign
Author(s) -
S. Haddadi,
Philippe Hamel,
G. Beaudoin,
I. Sagnes,
Christophe Sauvan,
Philippe Lalanne,
Juan Ariel Levenson,
A. M. Yacomotti
Publication year - 2014
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.22.012359
Subject(s) - photonic crystal , optics , radius , coupling strength , hexagonal lattice , wavelength , photonics , coupling (piping) , physics , sign (mathematics) , lattice (music) , coupled mode theory , materials science , yablonovite , molecular physics , condensed matter physics , photonic integrated circuit , refractive index , mathematical analysis , computer security , mathematics , antiferromagnetism , computer science , acoustics , metallurgy
We demonstrate a large tuning of the coupling strength in Photonic Crystal molecules without changing the inter-cavity distance. The key element for the design is the "photonic barrier engineering", where the "potential barrier" is formed by the air-holes in between the two cavities. This consists in changing the hole radius of the central row in the barrier. As a result we show, both numerically and experimentally, that the wavelength splitting in two evanescently-coupled Photonic Crystal L3 cavities (three holes missing in the ΓK direction of the underlying triangular lattice) can be continuously controlled up to 5× the initial value upon ∼ 30% of hole-size modification in the barrier. Moreover, the sign of the splitting can be reversed in such a way that the fundamental mode can be either the symmetric or the anti-symmetric one without altering neither the cavity geometry nor the inter-cavity distance. Coupling sign inversion is explained in the framework of a Fabry-Perot model with underlying propagating Bloch modes in coupled W1 waveguides.