Computers are an important symbol of the information age and a key support for information technology. With the application of artificial intelligence in various fields, the demand for computing power is experiencing explosive growth. On one hand, semiconductor processes have approached the physical limits of electronic chips, and the development of electronic computing faces two major bottlenecks: “speed” and “power consumption,” leading to three technical barriers: power wall, memory wall, and I/O wall. Currently, the computing-to-memory ratio and computing-to-I/O ratio are both 1-2 orders of magnitude lower than ideal conditions, and enhancing computing performance by reducing chip feature sizes faces significant challenges. On the other hand, the advanced process equipment for high-performance electronic chips is not yet fully autonomous in our country, posing a “bottleneck” risk. Compared to electronics, photons, as bosons, have unique advantages such as high transmission speed, high parallelism, high bandwidth, low power consumption, and low latency. Therefore, using optical technology to achieve high-performance information processing and computing is an inevitable trend. Traditional free-space optical computing methods cannot achieve miniaturization, and photonic integration is regarded as the only technological means to solve this problem. Since the 21st century, photonic chips have undergone rapid development from individual components to large-scale integration, demonstrating significant advantages in ultra-high-speed communication, high-performance computing, large-capacity optical interconnects, and high-precision optical sensing. There is a consensus in academia and industry: Optoelectronic integrated chips are expected to continue Moore’s Law, and using optoelectronic integrated chips for information interaction is a key technology and effective way to break through the bottleneck of electronic computer development, potentially alleviating or even solving China’s “chip pain.”
Silicon photonic chips integrate advanced microelectronic processing technology and cutting-edge photonics theory, incorporating photonic information components such as lasers, optical waveguides, optical modulators, and photodetectors on silicon-based chips, using photons as information carriers to achieve information transmission, interaction, and computation. Compared to traditional electronic technology, silicon photonic technology shows significant advantages in the speed and energy efficiency of information processing, providing strong support for the continuation of Moore’s Law. In recent years, silicon photonic information technology has received high attention and emphasis globally, with developed countries and regions such as the United States and the European Union incorporating optoelectronic integration technology into national strategic development plans. As early as 2015, the United States announced the establishment of a national-level integrated photonics manufacturing institute (AIM Photonics), composed of 124 entities from government, academia, and industry, including 50 companies such as IBM and Intel, over 20 universities including MIT and Stanford, 33 colleges, and 16 organizations. The EU has also successively formulated information and communication technology plans ICT27, ICT28, and “Horizon 2020,” with the core content aimed at promoting the development of the photonic integration industry. Our country has synchronized with international strategic layouts in the field of silicon photonics and continues to invest, clearly defining development goals and strategic needs for integrated circuits and next-generation artificial intelligence technology from the national “13th Five-Year” to “14th Five-Year” plans. The Ministry of Science and Technology, the Chinese Academy of Sciences, and other national science and technology teams have also deployed related pilot projects and major scientific projects, including building advanced optoelectronic chip manufacturing process platforms, forward-looking explorations of optoelectronic chips, and improving the industrial ecosystem of optoelectronic chips to solve the “chip pain” of China’s optoelectronic information industry and enhance our voice in the optoelectronic industry.
In today’s era of massive data processing and explosive growth in computing power demand driven by artificial intelligence, silicon photonic technology plays a crucial role in modern information technology and will bring disruptive technological innovations across multiple fields. The key to applying artificial intelligence technology is enhancing computing power. In high-performance computer architectures, adopting accelerator system structures that match specific application modes is an effective way to improve computing energy efficiency and reduce power consumption. A typical successful example is achieving orders of magnitude energy efficiency improvement through the matching of streaming computing applications with graphics processing unit chips. However, when facing applications in areas such as brain-like computing, deep learning, and intelligent perception, using von Neumann architecture-based electronic computers for matching acceleration shows poor results, while optical neural networks demonstrate unique advantages in this regard. Optical matrix operations possess characteristics of temporal and spatial parallelism and large propagation capacity. The deep learning algorithms of optical neural networks can be directly mapped, rather than simply simulating neural networks. By combining the capacitive-free effect characteristics of optical computing pathways, the energy efficiency of neural network computers based on optical matrix operations can be greatly enhanced, thus breaking through the constraints of the power wall. In terms of information transmission and interaction, the demand for ultra-low latency, ultra-high transmission rates, and lower energy consumption for information interaction in data centers during the big data era is continuously growing. Optoelectronic integration technology can achieve orders of magnitude optimization in information interaction capacity, device size, and data transmission energy efficiency. In satellite laser communication and deep space exploration, optoelectronic integrated chips are expected to revolutionize traditional communication terminals, establishing faster, stronger, and more stable high-speed routes between space and ground, accelerating the development of “integrated air and space.” Silicon photonic technology, through the optical transmission and electrical control approach, brings enormous imaginative space for new types of optoelectronic hybrid supercomputing, opening new paths for achieving ultra-high computing power. The arrival of the intelligent driving era imposes stringent demands on the perception capabilities of vehicles, and silicon photonic technology is expected to revolutionize automotive laser radar systems, establishing safer and more efficient intelligent driving systems. Additionally, silicon photonic technology has significant application potential in high-precision, high-sensitivity biosensing, precision medical diagnostics, and health monitoring.
While silicon photonic technology has brought disruptive changes in many information technology fields, it also faces multiple challenges during its development. On one hand, compared to electronic chips, photonic chips have multi-material characteristics, often requiring the integration of various materials to fully enhance the potential of photonic technology. Therefore, the integration and compatibility of heterogeneous materials and various functional devices have become urgent scientific problems that need to be solved, along with addressing the optoelectronic thermal coupling issues arising from heterogeneous integration. On the other hand, silicon photonic chips still struggle to solve the problem of photonic storage, thus requiring higher demands for the interaction between photonic information processing chips and storage chips. Establishing high-speed communication interfaces between silicon photonic chips and storage devices becomes critical, presenting challenges for the design of optical devices and optoelectronic fusion architectures. Improving the performance of information processing systems requires matching the information interaction speed between processors and the computing speed of processors to fully unleash the computing performance of processors. Although silicon photonic technology faces numerous challenges, it is still regarded as one of the disruptive disciplinary directions of the 21st century. With the continuous investment of scientists worldwide in the fields of silicon photonic chips and silicon photonic microsystems, along with a series of theoretical breakthroughs and application model validations, silicon photonic technology has gradually integrated with electronic technology, promoting the extensive application of optoelectronic microsystems and related industrial upgrades.
The increasingly fierce global competition makes us more aware that: science and technology, as the primary productive force, and the autonomy of core technologies directly relate to national security. The heavy reliance on imports for high-end chips poses significant risks. As an emerging technology independent of electronic integration technology, silicon photonic technology is at the forefront of global science and technology. Due to its strong foresight and practical value, it has become a technological strategic high ground that countries around the world are competing for. Silicon photonic chips do not require the most advanced semiconductor process equipment, freeing them from dependence on high-precision processing equipment, and high technical barriers have not yet formed, meaning that Europe and the United States do not have an absolute competitive advantage in this field, which does not pose a “bottleneck” suppression for our country.
Core technologies cannot be obtained through begging; they must be achieved through self-reliance. In response to the world’s technological frontiers and national strategic needs, our country has made forward-looking deployments and continuous investments in the field of optoelectronic integration. A large number of research institutions and universities, including the Chinese Academy of Sciences, have actively taken responsibility, forming research teams for optoelectronic integrated chips, aiming to leverage the advantages of organized research to accelerate original innovation and tackle key technologies. They have accumulated rich experience and technology in basic unit components and cultivated a group of young scientific and technological talents, establishing a good “industry-university-research integration” technology development ecosystem, contributing to achieving high-level technological self-reliance and strength for the “future optoelectronic integrated chips”.
Source: Learning Times
