Photonic integration of lithium niobate micro-ring resonators onto silicon nitride waveguide chips by transfer-printing

TL;DR

This paper demonstrates the first heterogeneous integration of lithium niobate micro-ring resonators onto silicon nitride chips using transfer-printing, achieving high Q-factors suitable for photonic applications.

Contribution

It introduces a novel transfer-printing method for integrating lithium niobate micro-ring resonators onto silicon nitride platforms, enabling scalable photonic device fabrication.

Findings

Achieved transfer of lithium niobate micro-ring resonators onto silicon nitride chips.

Obtained a high loaded Q-factor of over 32000 in the resonators.

Demonstrated functional ring resonator transmission spectrum in the 1.5-1.6 μm range.

Abstract

The heterogeneous integration of lithium niobate photonic waveguide devices onto a silicon nitride waveguide platform via a transfer-printing approach has been demonstrated for the first time. A fabrication process was developed to make free-standing lithium niobate membrane devices compatible with back-end integration onto photonic integrated circuits. Micro-ring resonators in membrane format were lithographically defined by using laser direct writing and plasma dry etching. The lithium niobate micro-ring resonators were then transferred from their host substrate and released onto a silicon nitride waveguide chip. An all-pass ring resonator transmission spectrum was obtained in the 1.5 {\mu}m to 1.6 {\mu}m wavelength range, with a measured loaded Q-factor larger than 32000.