Ultrabroadband thin-film lithium tantalate modulator for high-speed communications

• DOI: 10.1364/optica.537730
• Publication Date: 2024-10-28T14:00:07Z
• Authors: Chengli Wang; Dengyang Fang; Junyin Zhang; Alexander Kotz; Grigory Lihachev; Mikhail Churaev; Zihan Li; Adrian Schwarzenb...; Xin Ou; Christian Koos; Tobias J. Kippenberg
• Keywords: 0303 health sciences; 03 medical and health sciences

The continuous growth of global data traffic over the past three decades, along with advances in disaggregated computing architectures, presents significant challenges for optical transceivers in communication networks and high-performance computing systems. Specifically, there is a growing need to significantly increase data rates while reducing energy consumption and cost. High-performance optical modulators based on materials such as InP, thin-film lithium niobate (), or plasmonics have been developed, with excelling in high-speed and low-voltage modulation. Nonetheless, the widespread industrial adoption of thin-film remains compounded by the rather high cost of the underlying “on insulator” substrates—in sharp contrast to silicon photonics, which can benefit from strong synergies with high-volume applications in conventional microelectronics. Here, we demonstrate an integrated 110 GHz modulator using thin-film lithium tantalate ()—a material platform that is already commercially used for millimeter-wave filters and that can hence build upon technological and economical synergies with existing high-volume applications to offer scalable low-cost manufacturing. We show that the photonic integrated circuit based modulator can support 176 GBd PAM8 transmission at net data rates exceeding 400 LiNbO3. Moreover, we show that using silver electrodes can reduce microwave losses compared to previously employed gold electrodes. Our demonstration positions the modulator as a novel and highly promising integration platform for next-generation high-speed, energy-efficient, and cost-effective transceivers.