Open AccessLow-loss silicon slot waveguides and couplers fabricated with optical lithography and atomic layer deposition
Author(s) -
Antti Säynätjoki,
Lasse Karvonen,
Tapani Alasaarela,
Xiaoguang Tu,
Tsung-Yang Liow,
Marianne Hiltunen,
Ari Tervonen,
G. Q. Lo,
Seppo Honkanen
Publication year - 2011
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.19.026275
Subject(s) - materials science , silicon , waveguide , lithography , optics , coupling loss , optoelectronics , silicon photonics , electron beam lithography , atomic layer deposition , layer (electronics) , insertion loss , refractive index , resist , optical fiber , physics , nanotechnology
We demonstrate low-loss silicon slot waveguides patterned with 248 nm deep-UV lithography and filled with atomic layer deposited aluminum oxide. Propagation losses less than 5 dB/cm are achieved with the waveguides. The devices are fabricated using low-temperature CMOS compatible processes. We also demonstrate simple, compact and efficient strip-to-slot waveguide couplers. With a coupler as short as 10 µm, coupling loss is less than 0.15 dB. The low-index and low-nonlinearity filling material allows nonlinearities nearly two orders of magnitude smaller than in silicon waveguides. Therefore, these waveguides are a good candidate for linear photonic devices on the silicon platform, and for distortion-free signal transmission channels between different parts of a silicon all-optical chip. The low-nonlinearity slot waveguides and robust couplers also facilitate a 50-fold local change of the waveguide nonlinearity within the chip by a simple mask design.