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

The heterogeneous integration of pre-fabricated 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 3.2 x 104.

Automated summary

This study demonstrates the first heterogeneous integration of pre-fabricated lithium niobate photonic waveguide devices onto a silicon nitride waveguide platform using a transfer-printing approach. The fabrication process developed allows the compatibility of free-standing lithium niobate membrane devices with back-end integration onto photonic integrated circuits.