A broadband lithium tantalate-on-silicon nitride heterogeneous modulator for optical and terahertz communications and radar sensing.

Photonic integrated circuits have driven advances in optical interconnects, wireless communications, seamless sensing. Electro-optic modulators, which bridge the electronic and optical domains, act as the cornerstone of these systems. To address the ultra-broadband demands of next-generation information systems while enabling heterogeneous integration with other functional components, here we present a high-performance thin-film lithium tantalate-on-silicon nitride heterogeneous Mach-Zehnder modulator fabricated via micro-transfer printing. The device shows an insertion loss of 1.0 dB, an electro-optic bandwidth exceeding 110 GHz, and a power drift of ~0.3 dB over 72 h at quadrature bias. We employ the modulator for three typical scenarios in the applications of optical communications, fully photonic terahertz wireless communications, and radar sensing. It achieves optical data transmission rates beyond 375 Gbps, a record rate of 148 Gbps for wireless communications in the D-Band, and a range resolution of 1.2 cm with measured errors below 2 mm in the W-Band. These results pave the way for scalable, high-performance, cross-domain photonic chips for next-generation information networks.