While the term "Silicon Photonics" may seem unfamiliar to the general public, it has recently attracted significant R&D investment from industry giants such as Apple, Nvidia, Huawei, and TSMC. It represents the culmination of two of the 20th century's most critical inventions: the "Silicon Integrated Circuit" and the "Semiconductor Laser."
Why is Silicon Photonics Needed?
A primary driver for the development of silicon photonics—and its emergence as a potential high-growth market—is the demand from optical communications. Extending Moore's Law is becoming increasingly difficult; post-nanometer breakthroughs face formidable obstacles, including skyrocketing manufacturing costs and technical challenges like quantum tunneling.
Silicon photonics is a technology that integrates optical components (such as laser parts) with silicon-based integrated circuits. It uses light signals instead of electrical signals to achieve high-speed data transmission, longer transmission distances, and low power consumption. Additionally, it offers lower latency.
As demands for data transmission efficiency and computing performance grow rapidly, integrating optoelectronic components via semiconductor processes can not only increase component density and overall operational efficiency but also reduce energy consumption and effectively lower costs.
With the surging demand for massive computing in AI, communications, and autonomous vehicles, the evolution of IC technology under Moore's Law faces physical limits. How can we break through? The answer is moving towards light. Many domestic and international manufacturers are actively deploying silicon photonics technology. Combining electronics with photons is not only seen as a solution to signal transmission loss but is also regarded as a key technology to open a new chapter for Moore's Law and revolutionize the future.
Facing the major challenge of needing to move from electrical to optical signals to effectively and significantly boost massive data transmission efficiency, silicon photonics plays an indispensable role.
What is Silicon Photonics?
Silicon Photonics refers to integrated chips that transmit data by converting "electrical signals" into "optical signals." This simultaneously addresses the three goals of increasing transmission distance, increasing data bandwidth, and reducing unit energy consumption.
Because light has no charge or mass, signals within the same channel do not interfere with each other, and loss/heat generation is low—far superior to copper wire-based technologies. Standard optical communication wavelengths range from 1310nm to 1550nm, a range not absorbed by silicon. Furthermore, the use of SOI (Silicon On Insulator) technology is highly compatible with traditional silicon processes, effectively reducing costs.
Integrated Circuits (ICs) shrink billions of transistors onto a single chip to perform complex calculations. Silicon Photonics, essentially an integrated "optical" circuit, concentrates light-guiding pathways. Simply put, it converts "electrical signals" in the chip to "optical signals" on a silicon platform to conduct both electrical and optical signal transmission.
The Silicon Photonics Market
SEMI
The International Semiconductor Industry Association (SEMI) predicts that the global silicon photonics semiconductor market will reach 7.86 billion by 2030, with a Compound Annual Growth Rate(CAGR) of 25.7%, it has increased dramatically from just $1.26 billion in 2022, demonstrating tremendous growth potential.
Mordor Intelligence
Mordor Intelligence offers a more conservative forecast. They estimate the market size was 1.49 billion in 2023 and project it to reach 4.54 billion by 2028, with a CAGR of 24.98% during the forecast period (2023-2028).
Yole
According to Yole, the silicon photonics market (calculated by bare die) will climb from 152 millionin 2021 to 927 million in 2027. While many fields have reached a plateau, the silicon photonics market is just taking off, with a CAGR of 36%.
Markets and Markets
In 2015, Markets and Markets research indicated the global silicon photonics market was still in its nascent stage, valued at approximately 217.6 million. However, by 2022, the market crossed the 1 billion threshold, with a CAGR of 25.7%. Regionally, as major CSP data centers remain concentrated in the North American market, it accounts for 35.7% of the share; the Asia-Pacific region follows with 31.5%.
Technical Challenges and Development Bottlenecks
Silicon photonics faces significant challenges in "module integration." First, the cost of the silicon photonics device itself must be competitive; otherwise, there is no space for it to coexist with optical communication devices, nor can it demonstrate the advantages of silicon processes. Furthermore, the size of optical components like waveguides is usually fixed, whereas silicon-based components are constantly shrinking, creating a size discrepancy of dozens of times, making combination difficult.
There are also numerous challenges in component integration, specifically regarding interface communication. For instance, while semiconductor manufacturers understand electrical processes, photonic component performance is extremely sensitive to temperature and pathing. Line width and spacing in the process have a significant impact on optical signals. To develop more efficient photonic component structures and processes, a communication platform is needed to provide design specifications, materials, and parameters, facilitating information integration between optical and electronic manufacturers.
Moreover, because silicon photonics is currently used in niche markets, packaging processes and material standards are still being established. Most foundries providing silicon photonics chip services offer customized services or do not easily share them with other factories. The lack of a unified platform may hinder the development of silicon photonics technology. Beyond the lack of a common platform, high manufacturing costs, light source integration, component efficiency, material matching, thermal effects, and reliability are also bottlenecks. However, with continuous technological progress and innovation, these bottlenecks are expected to be overcome within the next few years to a decade.
Light Source Forms in Silicon Photonics
The technology for fabricating silicon-based integrated optical components on SOI substrates using standard CMOS processes is now mature. However, the laser light source remains the only part that cannot be epitaxially grown directly on the silicon substrate. Since silicon is an indirect bandgap material, it cannot emit light. Therefore, the light source must be introduced from the outside and assembled with the integrated circuit via packaging. Consequently, the optoelectronic integration benefit of silicon photonics is not yet complete, making the laser light source one of the biggest current challenges.
There are diverse ways to integrate lasers with silicon photonic integrated circuits, primarily constituting the light source in three ways. Among them, Flip Chip and Wafer Bonding are already used on production lines and are considered relatively mature technologies. However, direct epitaxy on silicon photonic integrated circuits offers the highest flexibility and lowest cost potential, so academic and R&D efforts continue to move in this direction.
Application Fields
Data Transmission
Silicon photonics uses light for transmission, which solves two major problems. If current data transmission is switched from electrical signals to silicon photonics optical signals, it will not only significantly improve transmission efficiency but also drastically reduce energy consumption, further improving heat dissipation issues.
● First, current transmission speeds are not fast enough. Even if chip computing power increases, if transmission speed cannot keep up with computing speed, data transmission latency or congestion occurs. In this scenario, no matter how fast the computing power is, it will be limited.
● Second, there is data transmission loss between servers. This leads to heat dissipation and energy loss issues. As AI infrastructure demands increase, the number of servers will inevitably rise, making the heat and energy losses associated with transmission a significant problem.
Non-invasive Glucose Monitoring
Integrating glucose monitoring capabilities into wearable devices is a goal major tech companies are striving for, with Apple being a representative example. To develop this feature, Apple previously partnered with Rockley Photonics, a UK-based silicon photonics startup. Although the partnership ended and Rockley Photonics filed for bankruptcy, Apple is reported to have made significant progress in non-invasive glucose monitoring.
According to Bloomberg, Apple is utilizing silicon photonics technology. The principle involves using a laser to emit light of specific wavelengths into the skin, where it is absorbed by interstitial fluid containing glucose, and then reflected back to a sensor to indicate glucose concentration. Reports suggest that this silicon photonics chip and sensor will be manufactured by TSMC.
LiDAR
In terms of sensing applications, silicon photonics is also gaining attention in autonomous vehicles and drones. LiDAR (Light Detection and Ranging) high-precision sensing is seen as key to the development of self-driving cars, but current development is limited by high costs and technical complexity. The future application of silicon photonics technology is expected to effectively reduce the size and cost of components installed in electric vehicles.
Fiber Optic Gyroscope
High-end gyroscopes used in drones have historically been too bulky and expensive for commercial drones. By adopting silicon photonics technology, fiber optic gyroscopes are expected to see significant reductions in cost and volume, likely appearing in consumer drone devices in the future.
Photonic Computing
Furthermore, the development of quantum computing and communication is expected to be driven by silicon photonics. According to Yole statistics, among silicon photonics applications, photonic processing will jump from being virtually non-existent in 2021 to becoming the second-largest application field by 2027. The consumer health market will rise to the third-largest application. Other areas with strong growth momentum include co-packaged engines, immunoassays, and optical interconnects, which Taiwanese manufacturers are actively developing.
Trends Among Manufacturers and Nations
United States
Led by IBM, which actively invested as early as 20 years ago, many enterprises, research units, and academic circles have subsequently joined in. Intel has invested in this technology for over 10 years and is the leading enterprise, being the fastest to launch mass-produced products with a market share reaching 50%.
At the Optical Fiber Communication Conference (OFC) in June 2024, Intel's Integrated Photonics Solutions (IPS) group demonstrated the industry's most advanced and first fully integrated Optical Compute Interconnect (OCI) chipset. This first-of-its-kind OCI chip supports 64 independent channels, each capable of transmitting data at 32 Gbps, effectively transmitting data over fiber optics up to 100 meters long. It is expected to meet the growing demands of AI infrastructure for higher bandwidth, lower power consumption, and longer transmission distances. It enhances connectivity between CPUs and GPUs in clusters and supports innovative computing architectures like coherent memory expansion and resource disaggregation.
Research units like Leti, Imec, and Ime have deeply cultivated this field for a long time. On the design side, companies such as Mellanox (acquired by Nvidia), Luxtera and Acacia (acquired by Cisco), Finisar, Arista, Broadcom, Marvell, Ranovus, and AMD have all invested in R&D.
Foundries
In wafer manufacturing, GlobalFoundries was the earliest investor. TSMC has actively deployed related technologies in recent years, co-developing next-generation silicon photonics technology with Luxtera in 2017. Later, in the packaging segment, it also deployed COUPE (Compact Universal Photonic Engine) heterogeneous integration technology for silicon photonics chips.
Industry rumors suggest that TSMC is developing new products based on silicon photonics technology with major clients Broadcom and Nvidia, with mass production already underway for 2025.
Taiwan
On September 3, 2024, at the Silicon Photonics International Forum during SEMICON Taiwan 2024, SEMI announced the formation of the SEMI Silicon Photonics Industry Alliance under the guidance of the Ministry of Economic Affairs. TSMC and ASE rallied over 30 participants, including ITRI, Browave, FOCI, Foxconn, MediaTek, Quanta, MSSCORPS, and Scientech, to build Taiwan's most complete silicon photonics cluster ecosystem and create next-generation key technologies.
China
China views this technology as a weapon for breaking through in semiconductor development, while Israel also lists it as a key national technology development project. Investment in the silicon photonics industry is substantial.
Because silicon photonics chip manufacturing can use existing, very mature semiconductor CMOS processes and equipment (with mainstream processes falling between 45 and 90 nanometers), China's semiconductor industry—which excels in IC design but lags in process technology—sees this as the best shortcut to drive its regional semiconductor "internal circulation" strategy. Taking Huawei as an example, its global acquisitions include the UK's Centre for Integrated Photonics (CIP Technologies) and Belgian silicon photonics developer Caliopa. The Chinese government has even established the "Optical Valley" in the East Lake High-tech Development Zone in Wuhan to fully build out silicon photonics-related technologies.
Packaging Technology
Silicon Photonics Advanced Packaging Technology
Currently, mainstream silicon photonics advanced packaging technologies include:
● Vertical Integration Packaging
● Co-Packaged Optics (CPO)
● Fiber Attach Packaging
● Waveguide-Based Packaging
● Glass Substrate Packaging
CPO
Among these, CPO (Co-Packaged Optics) is the packaging technology area where global chip manufacturers are concentrating their research. It is a highly integrated method that packages optical and electronic components together in the same package. This helps reduce the distance between optics and electronics, improving energy efficiency and performance for data center interconnects. Industry analysts state that as chip giants like TSMC, Intel, Nvidia, and Broadcom successively develop silicon photonics chips and the crucial Co-Packaged Optics (CPO) technology, the CPO market is expected to see explosive growth as early as 2024.
Packaging and testing giant ASE, after laying out related technologies for 20 years, has officially launched CPO packaging technology and successfully entered Broadcom's silicon photonics product supply chain.
Market for Silicon Photonics Advanced Packaging Technology
A research report published by the well-known research institution Spherical Insights predicts that from 2022 to 2032, the global Co-Packaged Optics market will grow at a compound annual rate of 68.9%. By 2032, the global CPO market is expected to reach 2.84 billion, compared to the institution's estimated market size of just 15 million in 2022.
Silicon Photonics Technology FAQ
Q: What is Silicon Photonics technology, and why does it address the limitations of traditional integrated circuits?
Silicon Photonics technology integrates optical components, such as laser parts, with silicon-based integrated circuits. It works by converting "electrical signals" into "optical signals" within the chip for transmission. This approach addresses the physical limits, high energy consumption, data transmission loss, and speed bottlenecks faced by traditional ICs as they struggle to continue Moore's Law.
Q:What are the core advantages of Silicon Photonics technology in the context of data transmission?
The core advantages of silicon photonics technology are its high speed, long distance, and low power consumption. Because light has no charge or mass, and signals do not interfere with each other, the loss and heat generation are much lower compared to copper-wire based technologies. This significantly improves transmission efficiency and reduces the heat dissipation and energy loss issues associated with the growing number of servers required by AI infrastructure.
Q:Besides data centers and optical communications, what other important application fields utilize Silicon Photonics technology?
In addition to optical communications and data transmission, silicon photonics technology is gaining attention in several other areas:
○ Non-invasive Glucose Monitoring: Used in wearable devices to detect glucose concentration through laser and sensor technology.
○ LiDAR (Light Detection and Ranging): Applied in autonomous vehicles and drones, where it is expected to effectively reduce component size and cost.
○ Fiber Optic Gyroscope: Expected to see significant reductions in volume and cost, enabling its use in consumer drones.
○ Photonic Computing: Expected to drive the development of quantum computing and communication, and is forecasted to become the second-largest application segment in the coming years.
Q:What are the main challenges and bottlenecks currently facing the development of Silicon Photonics technology?
The primary bottlenecks currently facing silicon photonics technology include:
○ Light Source Integration Challenge: Since silicon is an indirect bandgap material and cannot emit light, the laser light source must be assembled and integrated with the IC via packaging.
○ High Cost and Lack of Standardization: There is a lack of a unified communication platform, packaging processes and material standards are still being established, and manufacturing costs are high.
○ Module Integration Challenge: The size of optical components (like waveguides) is typically fixed, but silicon components are constantly shrinking, creating a significant size mismatch that makes integration difficult.
Q:Which major technology companies and countries are actively deploying or have made progress in Silicon Photonics technology?
Many tech giants and countries have invested in silicon photonics R&D:
○ US Companies: Intel (a leader with mass-produced products and a 50% market share), IBM (an early investor), and Nvidia, Broadcom, and Cisco. Intel demonstrated its Integrated Photonics Solutions (IPS) in 2024.
○ Foundries: GlobalFoundries was an early investor; TSMC has been actively deploying, developing new products with Broadcom and Nvidia.
○ China: Views it as a strategic area for semiconductor breakthrough, with Huawei actively pursuing R&D and acquisitions.
○ Packaging Technology: CPO (Co-Packaged Optics) is a key focus for global manufacturers; ASE has launched CPO technology and joined Broadcom's supply chain.
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