Buried-Electrode Hybrid Bonded Thin-Film Lithium Niobate Electro-Optic Mach-Zehnder Modulators
Forrest Valdez, Viphretuo Mere, Nicholas Boynton, Thomas A. Friedmann, Shawn Arterburn, Christina Dallo, Andrew Pomerene, Andrew Starbuck, Douglas C. Trotter, Anthony L. Lentine, Ashok Kodigala, Shayan Mookherjea
Abstract
Hybrid bonded silicon nitride thin-film lithium niobate (TFLN) Mach-Zehnder modulators (MZMs) at 1310 nm were designed with metal coplanar waveguide electrodes buried in the silicon-on-insulator (SOI) chip. The MZM devices showed greatly improved performance compared to earlier devices of a similar design, and similar performance to comparable MZM devices with gold electrodes made on top of the TFLN layer. Both devices achieve a 3-dB electro-optic bandwidth greater than 110 GHz and voltage-driven optical extinction ratios greater than 28 dB. Half-wave voltage-length products ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}\pi \text{L}$ </tex-math></inline-formula> ) of 2.8 and 2.5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}\cdot $ </tex-math></inline-formula> cm were measured for the 0.5 and 0.4 cm long buried metal and top gold electrode MZMs, respectively.