Visible wavelength silicon nitride focusing grating coupler with AlCu/TiN reflector.
High-performance silicon nitride focusing grating couplers with AlCu/TiN reflectors for a visible wavelength (660 nm) have been designed and fabricated in a standard complementary metal-oxide-semiconductor pilot line. The influence of the bottom oxide cladding thickness on the grating decay length and efficiency is theoretically and experimentally investigated. It is shown how the metal reflector not only increases the efficiency but also allows reduction of the radiated beam size. Coupling efficiencies above 59% have been measured for compact focusing gratings.
Integrated Photonics Laboratory, RWTH Aachen University, Aachen, Germany. sromero@iph.rwth‑aachen.de
Sebastian
S
Romero-García
Florian
F
Merget
Frank
F
Zhong
Hod
H
Finkelstein
Jeremy
J
Witzens