Illuminating the Future: Developments in PRC Photonic Chip Production

Executive Summary:

• In June, the first pilot production line for photonics microchips in the People’s Republic of China (PRC) was launched at Shanghai Jiao Tong University’s Chip Hub for Integrated Photonics Xplore (CHIPX), as the country explores new approaches to chip design.
• The PRC sees photonic technologies and chips as a potential to underpin many of the technological solution, offering superior speed, energy efficiency, scalability, and higher bandwidth, paving the way for future technological advancements.
• Xi Jinping, as shown in the PRC’s 14th Five-Year Plan and other national strategies, has emphasized photonics, leading to substantial investments aimed at reducing reliance on foreign semiconductor technology and achieving global leadership.
• The PRC’s advancements by academic institutes and Huawei in photonic technology aim to revolutionize the nation and military with chips potentially 1000 times faster than their electronic counterparts. These developments carry significant national security implications, potentially reshaping the US-China technological competition and export control policy. The situation warrants close monitoring.

At the end of June, the People’s Republic of China (PRC) marked a technological milestone by launching its first pilot production line for photonic microchips. The new facility, established by the Shanghai Jiao Tong University Chip Hub for Integrated Photonics Xplore (CHIPX), is intended to accelerate the development and application of photonics technology in the PRC (Xinhua, June 11).

The pilot production line, which saw its first batch of equipment installed in early January, aims to make “breakthroughs in the critical core technologies of optoelectronic information.” The primary focus of this production line is to advance new-generation information technologies and their industrial applications. The core technologies being developed include quantum computers, photonic processors, three-dimensional optical interconnection chips, and high-precision femtosecond laser direct writing machines (which are used in chip fabrication) (Sina, June 17). This initiative is part of a wider goal of harnessing photonics technology, which could prove important for advancing the PRC’s technological independence and undermining current US efforts to restrict the PRC’s development of its chip sector.

Photonics: Revolutionizing Chips, Quantum Computing, Telecommunications

Photonics technology uses photons—light particles—to transmit, process, and manipulate information. Photonic computing, a subfield of photonics, includes the design of optoelectronic circuits—chips that use photons instead of electrons to achieve high-speed, high-capacity data transmission. If manufacturing of these chips can scale up, costs come down, and they can be integrated with electronic systems, then photonic chips could underpin much future information processing and communication, especially as traditional electronic chips approach their physical and operational limits (Synopsys, last accessed June 30).

Photonic chips offer several advantages over electronic ones. In short, they can be faster, smaller, more energy-efficient, more scalable, able to handle much larger bandwidth, and able to transmit data more reliably and with lower latency (Nature, December 23, 2015). Some experts have suggested that photonic chips potentially offer a 1,000-fold improvement in computational speed compared to current silicon-based chips (Sohu, April 13). All this makes them suitable for high bandwidth, low latency scenarios, such as in data centers, telecommunications, high-frequency trading and real-time data analytics. [1] Back in 2020, Nick Harris, the CEO of a leading American photonics startup called Lightmatter, claimed that his firm’s chips could reduce AI data centers’ energy consumption by a factor of 20 and shrink the chips’ physical footprint by a factor of five compared to current technologies. The company also claimed that their chips would surpass Nvidia’s leading chip at the time, the A100, in both energy efficiency and throughput (EE Times, August 24, 2020; see also Semianalysis, August 22, 2022).

Photonics is still an emerging field, but photonics technologies already being integrated with existing technologies and global companies are also already investing in them (Nikkei Asia, January 29). For instance, Taiwan Semiconductor Manufacturing Company (TSMC) has assembled a team of about 200 researchers focused on ultra-high-speed silicon photonic chips and is collaborating with Broadcom and Nvidia, with production expected to start in late 2024. TSMC’s Vice President of System Integration Yu Zhenhua (余振華) has argued that these chips could address critical issues of energy efficiency and computing power in AI applications, potentially increasing computational power for large language models (LLMs) (Baidu, September 17, 2023). IBM, Google, and Intel, meanwhile, are investing in photonic quantum computing.

Silicon-based photonics, for instance, integrates photonic and electronic components on a single silicon chip using mature semiconductor CMOS (Complementary Metal-Oxide-Semiconductor) processes (China Energy News, June 3). This allows for the development of high-density, low-cost, and energy-efficient photonic devices (163, February 29). Microwave photonics, meanwhile, uses optical components to process and compute analog electronic signals with faster speeds and higher energy efficiency than traditional electronic processors, and could dramatically improve telecommunications systems, wireless communication systems, high-resolution radar systems, AI, computer vision, and image and video processing (Nature, February 28).

Photonics increasingly plays a role in quantum computing. Some quantum computers now use photons to represent quantum bits (aka qubits—basic units of quantum information). This offers the similar advantages of speed, scalability, and energy-efficiency over electron-based quantum information processing seen in other photonics applications (Baijiahao, June 11). As such, photonic quantum computers can operate at room temperature, unlike superconducting qubits that require extremely low temperatures. This makes them more practical and potentially more accessible (Zhihu, November 24, 2023). Jin Xianmin (金贤敏), founder of leading PRC quantum computing startup TuringQ (图灵量子), has argued that photonic quantum computing meets the essential criteria for developing general-purpose quantum computers (Wenwui, June 17; TuringQ, accessed July 2).

Xi, PLA, Government Focus on Photonics

Since at least 2015, the PRC has incorporated its commitment to advancing photonics technology into its national strategy. That year, the Ministry of Science and Technology (MOST) convened experts in Beijing to evaluate the “Photonics Integration Technology and System Applications (光子集成技术与系统应用)” project. Led by the Chinese Academy of Sciences’ Institute of Semiconductors, the project involved prominent institutions such as Zhejiang University, Peking University, and Nanjing University. It achieved breakthroughs in designing, packaging, and testing high-density silicon-based photonic waveguide devices—components that direct light signals with minimal loss, enabling high-speed and high-capacity data transmission (MOST, October 20, 2015).

In the 14th Five-Year Plan, a section on strengthening the power of the country’s strategic technology includes photonics in a list of technologies for which national labs should be built (State Council, March 13, 2021). MOST has also instituted an “Information Photonics Technology (信息光子技术)” project, aimed at boosting research and development (R&D) in this area (SKL-PET, May 11, 2021). The National Natural Science Foundation has also funded several early photonics projects, while MOST has included it in its own R&D plans (NSFC, November 26, 2020; OE Journal, November 30, 2023).

Xi Jinping has personally provided his imprimatur to the photonics industry. During an inspection of a leading photonics company in 2022, Xi Jinping remarked that the photonic-electronic industry “is a widely applied strategic high-tech industry, and it is also a high-tech industry in which our country has the conditions to achieve breakthroughs ahead of others.” [2]

There are four aspects to the PRC’s officially mandated focus on photonics. First, the PRC recognizes that traditional integrated circuits are reaching their physical limits and that the challenges associated with them—such as increased heat generation, energy consumption, and signal interference—are becoming more pronounced. By pivoting early to focusing on photonic chips, the PRC hopes to capitalize by providing the next generation of chips (China Energy News, June 3).

Second, the PRC views photonics as a means of leapfrogging its competitors in the global semiconductor race, which has historically been dominated by Western countries. By investing heavily in R&D, the country aims to overcome its deficiencies and reduce its reliance on foreign semiconductor technology. Sui Jun (隋军), president of SinTone (中科鑫通), asserts that photonic chip production enables the PRC to innovate without relying on extreme ultraviolet (EUV) lithography, the most advanced machine tool for fabricating chips that the PRC cannot produce and is currently restricted from importing (ChinaAET, December 12, 2022).

Third, the ability to efficiently process and analyze vast amounts of data at speed is increasingly important as the amount of data grows exponentially (MIT Technology Review China, November 23, 2020). Photonics technology is therefore seen as the foundation for future information technologies, as it can support large-scale data centers, high-speed communication networks, and advanced AI applications—all of which are hoped will reenergize the PRC’s economic growth and enhance its technological leadership.

Last, experts within the People’s Liberation Army (PLA) are also studying potential applications of photonics technology, particularly in the field of microwave photonics. According to researchers from the Nanjing Electronic Devices Institute and the Second Military Representative Office of the Air Force Equipment Department in Nanjing, microwave photonics is considered a disruptive technology that can address many of the electronic bottlenecks currently faced by microwave radar equipment. They recognize that microwave photonic technology holds immense potential for applications in radar, satellite communications, broadband wireless access networks, and integrated space-air systems, promising to profoundly impact the advancement of modern information technology (Journal of Radars [雷达学报], 2019).

Breakthroughs in PRC Research

PRC researchers have announced breakthroughs in recent years that have often flown under the radar of observers in the West. One notable example is the development by Tsinghua University of the Taiji Photonics Chip (太极光芯片), which allegedly outperforming current smart chips by two to three orders of magnitude (Baijiahao, April 12). This chip is framed as being especially useful for complex tasks such as analyzing large-scale images, supporting LLM training and inference, and operating low-power autonomous intelligent systems. In other words, this technology can be applied to complex classification tasks and AI-generated content.

Huawei is also making strides in photonics. The company filed a patent for a “photonic chip, its preparation method, and its communication device (光芯片及其制备方法、通信设备)” in 2021, for instance (Baijiahao, March 13). At the 2021 Huawei Global Analyst Summit, Xu Wenwei (徐文伟), President of Huawei’s Strategic Research Institute, predicted that computing power demand will increase 100-fold by 2030, leading to heavy investment by Huawei in research in photonic computing (Youtube/Huawei, April 12, 2021).

Another advance comes from a team under Professor Wang Cheng (王騁) at the City University of Hong Kong, which has also developed what it describes as a “world-leading microwave photonic chip.” This chip uses optical components to process and compute analog electronic signals at speeds 1,000 times faster than traditional electronic processors while consuming less energy, and is intended for use in a wide range of applications (CityU, February 29). Professor Wang’s team overcame challenges with integrating photonics with electronic systems by developing a chip with ultrafast electro-optic conversion modules, using an artificial crystal known as Lithium Niobate.

Lithium niobate (LiNbO3) is often referred to as the “silicon of photonics” and is increasingly being used in photonic applications (Springer, January 1, 2012). Initially developed through collaborations between Harvard University, Nokia Bell Labs, and PRC researchers back in 2018, lithium niobate on insulator (LNOI) platforms have paved the way for high-performance photonic devices (Nature, April 18, 2018). The material’s properties make it well-suited for these purposes, and LNOI devices have captured 99 percent of the high-speed modulation market (CHIPX, last accessed June 30; IOPTEE, last accessed June 30).

Challenges persist, however. PRC experts argue that photonic materials like thin-film lithium niobate lack standardized processing techniques, which hampers the development of related devices and chips. Photonic devices are highly sensitive to temperature and manufacturing errors, necessitating high-precision real-time detection and repair technologies for large-scale integration (NSFC, January 17, 2023). Foreign experts, meanwhile, have focused on key obstacles such as power loss from passive components, delay lines, switches, and chip interconnects, which impede the performance of integrated photonic circuits (Nano Material Science, April 11).

To fully leverage benefits of photonics such as high speed, high bandwidth, and low energy consumption, the development of next-generation ultralow-loss components using multimode waveguide technology and materials like silicon or silicon nitride is essential (Nano Material Science, April 11). This involves overcoming bottlenecks related to bandwidth, noise, loss, sensitivity, and extending operational wavelengths. One critical component is high-density integrated transceiver chips for optical communication, which are capable of increasing parallel channels and breaking transmission capacity limits. Intel’s 1.6 TB/s 8-wavelength multiplexed silicon photonic communication chip illustrates the challenge. The laser and modulator components occupy most of the chip area, indicating that current sizes and integration levels are insufficient for future ultra-high-capacity needs (Intel, June 28, 2022).

Conclusion

The PRC’s launch of its first photonic chip production line is significant. It is set to drive innovations in quantum computing, photonic processors, and advanced communication technologies. Strategic investments in photonics by the state, as highlighted in the 14th Five-Year Plan and other high-level endorsements, is helping to position the PRC at the forefront of this critical technology, as well as to help it circumvent US tech controls.

Whether the PRC can convert its alleged research breakthroughs into scalable production of devices based on this new technology remains to be seen. Currently, no country has the capability to harness this technology for mass production beyond proof of concept and limited prototypes (Nature, May 8). Nevertheless, the PRC has made a bid to lead in this emerging sector, laying out the pathway and marshalling the necessary resources. The potential gains that photonics represents for an array of technologies with national security implications makes it imperative that future developments are watched closely.

Notes

[1] Gupta, Rajeev et al. “The integration of microelectronic and photonic circuits on a single silicon chip for high-speed and low-power optoelectronic technology.” Nano Materials Science, 2024. https://doi.org/10.1016/j.nanoms.2024.04.011.

[2] Gong, 2023.