Mass-producible! China Achieves Breakthrough in High-Performance Photonic Chip Technology

As the integrated circuit industry enters the "post-Moore era," the challenges and costs associated with enhancing the performance of IC chips are steadily rising, making it increasingly urgent to explore innovative technological solutions. Recently, a research team from the Shanghai Institute of Microsystem and Information Technology under the Chinese Academy of Sciences has achieved a groundbreaking breakthrough in the field of lithium tantalate heterogeneous integration wafers and high-performance photonic chips, successfully developing a new type of "optical silicon" chip that can be mass-produced. The related research findings were published online on August 8 in the prestigious journal *Nature*.

Currently, integrated optoelectronic technologies—led by silicon photonics and thin-film lithium niobate photonics—are groundbreaking solutions that address the performance bottlenecks plaguing conventional integrated circuit chips. Lithium niobate, often dubbed the "optical silicon," has garnered significant attention in recent years, with leading international research institutions like Harvard University even proposing a plan to build a new-generation "Lithium Niobate Valley," modeled after the renowned "Silicon Valley" ecosystem.

"Similar to lithium niobate, lithium tantalate can also be dubbed 'optical silicon.' Our research, conducted with collaborators, has demonstrated that single-crystal lithium tantalate thin films exhibit outstanding electro-optic conversion properties—and in some aspects, they even outperform lithium niobate," says Ou Xin, the paper’s co-corresponding author and a researcher at the Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences. "More importantly, the fabrication process for silicon-based lithium tantalate hetero-wafers closely resembles the techniques used to produce silicon-on-insulator wafers, making it possible to achieve low-cost, large-scale manufacturing of lithium tantalate films. This not only highlights their immense practical value but also paves the way for widespread adoption in next-generation optical devices."

This time, the research team employed a hetero-integration technique based on the "universal ion knife," using ion implantation combined with wafer bonding to fabricate high-quality silicon-based lithium tantalate single-crystal thin-film heterogeneous wafers. Meanwhile, in collaboration with another team, they jointly developed an ultra-low-loss micro- and nanofabrication method for lithium tantalate photonic devices, successfully producing lithium tantalate photonic chips.

We highlight that lithium tantalate photonic chips exhibit exceptional features such as extremely low optical loss and highly efficient electro-optic conversion, making them a promising solution to address the four major bottlenecks in the communications field—speed, power consumption, frequency, and bandwidth—and potentially paving the way for groundbreaking technologies in areas like cryogenic quantum computing, optical computing, and optical communication.