Centimetre-Scale Micro-Transfer Printing to enable Heterogeneous Integration of Thin Film Lithium Niobate with Silicon Photonics

TL;DR

This paper presents a novel centimetre-scale micro-transfer printing technique to integrate thin-film lithium niobate with silicon nitride photonics, enabling active functionalities while maintaining low propagation losses.

Contribution

It introduces a micro-transfer printing method for integrating long TFLN devices onto SiN platforms, preserving high-speed electro-optic properties and low losses.

Findings

Achieved centimetre-scale TFLN integration with SiN platform.

Demonstrated high-speed modulation up to 35 GHz.

Measured low propagation and transition losses.

Abstract

The integrated photonics CMOS-compatible silicon nitride (SiN) platform is praised for its low propagation loss, but is limited by its lack of active functionalities such as a strong Pockels coefficient and intrinsic \c{hi}(2) nonlinearity. In this paper, we demonstrate the integration of centimetre-long thin-film lithium niobate (TFLN) devices on a SiN platform using the micro-transfer printing (uTP) method. At a wavelength of 1550 nm, propagation losses of approximately 0.9 dB/cm and transition losses of 1.8 dB per facet were measured. Furthermore, the TFLN was integrated into an imbalanced push-pull Mach-Zehnder modulator, achieving a V{\pi} of 3.2 V. The electro-optics nature of the observed modulation is confirmed by measuring the device up to 35 GHz, showing that the printing does not affect the high-speed LN properties.