Open AccessBroadband polarization independent nanophotonic coupler for silicon waveguides with ultra-high efficiency
Author(s) -
Pavel Cheben,
Jens H. Schmid,
Shurui Wang,
DanXia Xu,
Martin Vachon,
Siegfried Janz,
J. Lapointe,
Yves Painchaud,
Marie-Josée Picard
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.23.022553
Subject(s) - nanophotonics , optics , materials science , optoelectronics , coupling loss , silicon photonics , silicon , photonic integrated circuit , polarization (electrochemistry) , photonics , silicon on insulator , optical fiber , physics , chemistry
Coupling of light to and from integrated optical circuits has been recognized as a major practical challenge since the early years of photonics. The coupling is particularly difficult for high index contrast waveguides such as silicon-on-insulator, since the cross-sectional area of silicon wire waveguides is more than two orders of magnitude smaller than that of a standard single-mode fiber. Here, we experimentally demonstrate unprecedented control over the light coupling between the optical fiber and silicon chip by constructing the nanophotonic coupler with ultra-high coupling efficiency simultaneously for both transverse electric and transverse magnetic polarizations. We specifically demonstrate a subwavelength refractive index engineered nanostructure to mitigate loss and wavelength resonances by suppressing diffraction effects, enabling a coupling efficiency over 92% (0.32 dB) and polarization independent operation for a broad spectral range exceeding 100 nm.