Centimetre-scale micro-transfer printing to enable heterogeneous integration of thin film lithium niobate with silicon photonics

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 χ(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 (µTP) 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 Vπ of 3.2 V. The electro-optic 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.