Open AccessBroad-band surface optical coupler based on a SiO2-capped vertically curved silicon waveguide
Author(s) -
N Atsumi,
Tomoya Yoshida,
Emiko Omoda,
Youichi Sakakibara
Publication year - 2018
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.26.010400
Subject(s) - optics , materials science , waveguide , coupling loss , chemical vapor deposition , output coupler , collimated light , optoelectronics , gaussian beam , silicon , optical fiber , beam (structure) , physics , laser , resonator
A chip-surface optical coupler based on a vertically curved Si waveguide was demonstrated for coupling with high-numerical-aperture single-mode optical fibers with a mode-field diameter of 5 µm. This device features a dome-like SiO 2 coupler cap, which acts as collimation lens. We succeeded in fabricating this structure using an isotropic SiO 2 deposition technique employing plasma-enhanced chemical vapor deposition and obtained a light output that approximates that of a 5-µm-waist Gaussian beam. The fabricated coupler showed a coupling loss of less than 4.2 dB and a 0.5-dB-loss bandwidth above 150 nm for TE-polarized light.