China's photonic chip debut to power AI, 6G and quantum computing push: expert

The Star

13-06-2025

As China joins the international drive to mass produce high-performance photonic chips, an industry pioneer said the technical performance of its chips will position the country for major advances in artificial intelligence (AI), 6G and quantum computing.
Shanghai Jiao Tong University Chip Hub for Integrated Photonics Xplore (CHIPX) announced on June 5 that it had begun producing 6in (15.2cm) wafers for thin-film lithium niobate (TFLN) photonic chips, which rely on light – or photons – rather than electrical signals for information transmission and processing.
While this is China's first pilot production line for photonic chips, Europe and the US are already established in the field. Dutch company SMART Photonics last year upgraded its line to process 4in InP wafers, and California-based PsiQuantum revealed in February that it was adapting a 300mm silicon photonics line.
China's pilot production line, built on the new TFLN material, may have come later but it is already showing gains in terms of technical performance by overcoming a global limit for high-speed optical links.
TFLN is an emerging high-performance optoelectronic material known for its ultra-fast electro-optic effect, high bandwidth and low power consumption. But its brittle nature has hindered large-scale manufacturing.
'Establishing this stable production line is the result of nearly 15 years of effort,' said Professor Jin Xianmin, director of CHIPX.
'I began working on photonic chips in 2010 and focused on lithium niobate from 2018,' Jin said. 'Before this pilot production line, we spent years refining fabrication techniques, building small-scale prototypes, and solving critical issues.
'For instance, achieving efficient coupling between electrodes and the optical chip required a long and technically demanding process from design to tape-out to testing.'
Construction of the pilot production line began in 2022 and took three years to complete. It houses more than 110 state-of-the-art fabrication tools using complementary metal-oxide-semiconductor technology, demonstrating full-chain technological self-reliance that includes photolithography, thin-film deposition, etching, wet processing, dicing, metrology and packaging – all tailored for 6in TFLN wafers.
'To ensure stability and reduce uncertainties in both materials science and fabrication techniques, the production line currently uses top-tier international equipment.
'In the future, we have the ability to gradually adopt domestic or refurbished alternatives, with some Chinese teams already able to provide third-party maintenance for the current machinery,' Jin said.
While the production process shares similarities with that of electronic chips, it is optimised for photonic applications. Unlike electronic chips, which prioritise miniaturisation and integration, photonic chips require exceptional surface smoothness.
The team has adapted techniques such as annealing, a type of heat treatment, to repair microscopic surface defects and improve optical performance.
Testing and process improvements allowed the team to achieve advanced results: the modulation bandwidth exceeded 110 gigahertz, overcoming a global limit for high-speed optical links; insertion loss dropped below 3.5 decibels and waveguide loss below 0.2 decibels/cm, greatly improving signal transmission.
Meanwhile, the modulation efficiency showed a clear boost in electro-optical performance.
'These lithium niobate photonic chips can function not only as computing servers themselves but also as critical components for photonic-electronic integration,' Jin said. 'They enable the high-speed connection of various computing resources.'
The institute envisions a computing architecture that merges optical transmission and optical computing, offering highly parallel, low-latency, and energy-efficient solutions for AI model training and inference.
With their ultra-low loss, high bandwidth and rapid signal transmission, lithium niobate modulators are also well suited for cloud computing, supercomputing centres, and future 5G and 6G infrastructure.
'Beyond computing and connectivity, photonic chips also hold promise for applications such as laser gyroscopes, lidar, and biosensing. The field has seen steady research progress over the years, but what it has lacked was a scalable production path,' Jin said.
The current pilot line has an annual capacity of 12,000 6in wafers and is capable of rapid, low-cost production. 'Previously, it could take up to a year to fabricate and test a single quantum photonic chip,' Jin said. 'Now, we are iterating weekly. This speed is critical for advancing quantum photonic technologies.'
China's photonics industry is gaining momentum, with companies such as Hangzhou's Xili Photonics recently securing major investments. Last month, CHIPX was named one of the Ministry of Industry and Information Technology's first batch of priority-cultivated pilot platforms.
'Our platform is currently a national pioneer,' Jin said. 'This production line can develop prototypes into small-batch production for scientists, research institutes and companies, while also accelerating the validation of cutting-edge technologies – from zero to one.'
CHIPX said it aimed to further stabilise its production process, increase yields, experiment with other materials, and eventually scale to 8in wafer fabrication. – South China Morning Post