Open AccessHighly efficient coupling of crystalline microresonators to integrated photonic waveguides
Author(s) -
Miles Anderson,
Nikolay G. Pavlov,
John D. Jost,
Grigory Lihachev,
Junqiu Liu,
Tiago Morais,
Michael Zervas,
M. L. Gorodetsky,
Tobias J. Kippenberg
Publication year - 2018
Publication title -
optics letters/optics index
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.524
H-Index - 272
eISSN - 1071-2763
pISSN - 0146-9592
DOI - 10.1364/ol.43.002106
Subject(s) - optics , materials science , coupling (piping) , integrated optics , photonic crystal , coupled mode theory , optoelectronics , photonic integrated circuit , refractive index , photonics , physics , metallurgy
Crystalline optical whispering gallery mode resonators made from alkaline earth fluorides can achieve exceptionally large optical finesse, and are used in a variety of applications, from frequency stabilization and narrow linewidth lasers, to low-noise microwave generation or soliton Kerr frequency combs. Here we demonstrate an efficient coupling method to resonators of these materials, which employs photonic integrated waveguides on a chip based on silicon nitride. By converting a mode from silicon nitride to a free-hanging silica waveguide on a silicon chip, coupling to a crystalline resonator is achieved with a high extinction, while preserving a quality factor exceeding 200 million. This compact, heterogeneous integration of ultra-high Q-factor crystalline resonators with photonic waveguides provides a proof of concept for wafer scale integration and robust, compact packaging for a wide range of applications.