Driving the Future of AI Datacenters with STMicroelectronics’ Silicon Photonics and BiCMOS Technologies.

An interview with Remi EL-OUAZZANE, President, Microcontrollers, Digital ICs and RF Products Group.

STMicroelectronics is committed to meeting hyperscalers demands for higher performance and better energy-efficiency in AI data centers. We enable the next generation of cloud infrastructure by driving innovations in Silicon Photonics (SiPho) and BiCMOS technologies.

Through strategic collaborations, ST delivers essential solutions for the future of high-performance AI computing clusters, specifically targeting upcoming 800Gb/s and 1.6Tb/s optical interconnects.

Remi EL-OUAZZANE, President, Microcontrollers, Digital ICs and RF Products Group, shares ST's vision for cloud optical interconnects and its strategic role in the rapidly evolving datacenter landscape.

Q1. Could you elaborate on ST's definition and strategic vision for cloud optical interconnects, particularly within the context of evolving data center architectures?
ST defines cloud optical interconnects as the foundational technology enabling the continued scaling and performance of modern data centers. These interconnects, utilizing optical fiber and advanced electro-optical transceivers, overcome the bandwidth and distance limitations of traditional copper-based solutions, facilitating high-speed communication between servers, switches, and accelerators.

ST's strategic vision centers on providing the key building blocks for these interconnects, leveraging our leadership in BiCMOS and silicon photonics to deliver solutions that meet the stringent demands of cloud-scale computing. We recognize the crucial role of these interconnects in supporting emerging AI workloads and are committed to pushing the boundaries of performance, power efficiency, and integration density.

Q2. How is ST strategically positioned within the silicon photonics supply chain to foster innovation and deliver differentiated value to its customers?
ST occupies a pivotal position within the silicon photonics ecosystem, acting as a trusted foundry partner and technology enabler - thanks to our unique IDM (Integrated Device Manufacturer) model. We provide advanced manufacturing capabilities based on our SiPho and BiCMOS platforms, coupled with comprehensive design and support services to our customers. Specifically, our PIC100 for SiPho and B55(X) for BiCMOS, manufactured in our 300mm facility in Crolles, France, stand as examples.

We're focused on fostering collaborative relationships with our partners across the value chain to ensure we can deliver optimal solutions. We believe that this collaborative approach, combined with our advanced manufacturing capabilities in Crolles, positions us to play a critical role in the ongoing evolution of the silicon photonics industry. We are focused on providing the building blocks, but not the end products, to enable a thriving and diverse ecosystem.

Q3. What key trends are driving the adoption of silicon photonics in the data center, and how is ST preparing to address the evolving needs of the market?
The adoption of silicon photonics is accelerating due to several key factors: the relentless demand for higher bandwidth, increased power efficiency, and smaller form factors in data centers. As AI workloads continue to grow, the limitations of traditional interconnect solutions become increasingly apparent. Datacenters are increasingly seeking solutions capable of handling the throughput demands of next-generation applications while minimizing energy consumption and footprint.

ST is committed to being at the forefront of this evolution. We're actively developing innovative silicon photonics and BiCMOS technologies that will allow our customers to meet these growing demands, which positions us well to capture a significant share of this expanding market. Our efforts are focused on enhanced performance (200Gbps per fiber), power efficiency, compact form factors, and high-volume production.

Q4. How does ST view the emerging market for optical I/Os, and what solutions is ST developing to address this market need?
ST recognizes the increasing importance of Optical I/Os in addressing the limitations of copper interconnects as AI clusters scale. Optical I/Os, integrated directly into GPU or switch packages, convert electrical signals to optical signals, facilitating high-bandwidth communication via fiber optics.

ST is providing the necessary toolkit for customers to design specific optical IOs devices, including TSV (Thru Silicon Via) and compact modulators, and advanced services such as test and pre-packaging. Silicon photonics is still the best candidate to address this application, because of compactness, thermal efficiency, easier coupling to the fiber, as well as a direct connection to standardized SERDES lanes.

Q5. How does ST's BiCMOS technology contribute to the performance and differentiation of its silicon photonics solutions?
Our BiCMOS technology is a key differentiator in our silicon photonics solutions, enabling superior performance and efficiency. ST's BiCMOS process offers best-in-class transistor characteristics and noise figures, translating to higher gain, better linearity, and lower power consumption in optical transceivers.

When combined with our SiPho technology, these advantages become even more pronounced. For example, the better signal quality enabled by ST BiCMOS can reduce or eliminate the need for error correction DSP, resulting in significant cost and power savings for our customers. ST BiCMOS allows significant system cost reduction, system power reduction and it delivers high quality and reliability high volume through 300mm manufacturing in our Crolles facility in France. This enables emerging standards like LPO (Linear Pluggable Optics).

Q6. What are the unique advantages of ST's SiPho and BiCMOS offerings in terms of manufacturing capabilities and supply chain?
Beyond the intrinsic performance advantages of our SiPho and BiCMOS technologies, we believe that a key differentiator is ST's ability to deliver them at high volume and high quality, using advanced manufacturing techniques. ST's SiPho and BiCMOS are manufactured in our 300mm facility in Crolles, France, a plant that is able to manufacture devices down to 18nm, guaranteeing optimal high-yield and reliability.

ST's independent supply chain also allows us to deliver more services to our customers, such as the electro-optical testing, packaging services as well as design services whenever required: a single-entry point to ease customers' life. This provides our customers with a single point of contact for their silicon photonics needs, streamlining the development process and reducing time to market.

Q7. Which types of customers are you targeting with your SiPho and BiCMOS solutions, and what is the nature of their interest at this stage?
The cloud optical interconnect ecosystem is complex, with hyperscalers (Alphabet, AWS, Meta, Azure, …) driving the market architecture and transceiver choices. While hyperscalers set directions, ST's direct customers are those companies designing EIC and PIC to be integrated into these optical transceivers.

The interest we are seeing for ST's SiPho and BICMOS in this vast ecosystem is very high: there is a clear understanding of the value proposition we are making and an even clearer acknowledgement of the technical benefits we are bringing.

Q8. How has ST leveraged its past experience to develop its current silicon photonics offering?
ST has a long history of innovation in silicon photonics and indeed was actually a pioneer; our first 300mm SiPho family (PIC25, for transceivers up to 50Gbps/lane) had several years of production in the 2010s. This early experience, combined with our ongoing investment in R&D and our established presence in the optical market via BiCMOS, has enabled us to develop a leading-edge silicon photonics offering tailored to the demands of today's datacenters. We leverage that expertise to provide best-in-class technical parameters for new generation of optical transceivers, enabled by our B55X process.

Q9. What are ST's long-term goals for market share and revenue in the silicon photonics market?
We view our investment in silicon photonics as a long-term strategic initiative, with a technology roadmap designed to support the evolving needs of the market for the decade to come. We anticipate that the combined foundry business of BiCMOS and SiPho would reach 2B$ SAM by 2030, thanks to the continuous growth of data center infrastructure and Al clusters. We are committed to working with our customers to capture a significant share of this growing market. We expect revenue to become significant in the coming years.

Remi EL-OUAZZANE
President, Microcontrollers, Digital ICs and RF Products Group at STMicroelectronics

Read more about ST silicon photonics technology: https://www.st.com/content/st_com/en/about/innovation-technology/silicon-photonics.html