Heterogeneously integrated lithium tantalate-on-silicon nitride modulators for high-speed communications.

Area of Science:

• Photonics and Materials Science
• Integrated Optics
• Electro-optics

Background:

• The Pockels effect is crucial for ultrabroadband integrated modulators.
• Lithium tantalate (LT) offers advantages over lithium niobate, including better photostability and higher optical damage threshold.
• Heterogeneous integration is key for combining material properties with established fabrication processes.

Purpose of the Study:

• To demonstrate wafer-scale heterogeneous integration of lithium tantalate films on silicon nitride photonic integrated circuits.
• To evaluate the performance of these integrated devices for high-speed data modulation.
• To establish LT-on-SiN as a viable platform for RF photonics and interconnects.

Main Methods:

• Wafer-scale heterogeneous integration of thin-film lithium tantalate on silicon nitride.
• Fabrication of low-loss silicon nitride photonic integrated circuits.
• Characterization of optical losses, half-wave voltage, and modulation bandwidth.
• High-speed data transmission experiments using PAM4 and 16-QAM signals.

Main Results:

• Achieved low optical losses of approximately 14.2 dB/m.
• Demonstrated devices with a 6 V half-wave voltage and modulation bandwidths up to 100 GHz.
• Successfully transmitted PAM4 and 16-QAM signals at net data rates of 333 Gbit/s and 581 Gbit/s, respectively.

Conclusions:

• Lithium tantalate-on-silicon nitride is a promising platform for high-performance photonic integrated circuits.
• This integration combines the benefits of silicon nitride waveguides with the ultrafast electro-optic response of lithium tantalate.
• The platform is suitable for applications in RF photonics, optical interconnects, and analog signal processing.