Grating couplers are one of the building blocks in silicon (Si) photonics. A lithium niobate-on-insulator (LNOI) platform has a wide transparency window, an exceptional electro-optic performance, and a favorable mechanical property. Here we propose a grating coupler on the LNOI platform for an optical fiber to an ultra-low-loss silicon nitride (Si3N4) waveguide. Titanium dioxide (TiO2) has a negative thermo-optic coefficient and can be used to compensate the temperature drift of cores with positive thermo-optic coefficients. Here, a TiO2 layer on the high-aspect-ratio Si3N4 core is used for the athermal operation. The fundamental TE mode at a wavelength of 1550 nm is used as an input from the ultra-low-loss waveguide. We achieve a high directionality of 68% at the fixed wavelength. A coupling efficiency of 48% can be obtained. A 3-dB bandwidth of 60 nm from 1520 to 1580 nm is presented by the proposed grating coupler.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.