SEMICON 2025 Silicon Photonics Summit: GlobalFoundries

Introduction

As global data generation grows explosively and demand for AI model training and supercomputing keeps climbing, traditional electrical interconnect can no longer sustain the enormous data transfer and compute energy. Silicon photonics, with its advantages in latency, bandwidth, density, signal integrity and power, has become a key technology for data centers and AI infrastructure.

At the SEMICON 2025 Silicon Photonics Summit, GlobalFoundries (GF) stressed that silicon photonics is no longer just an R&D topic but an industrial foundation moving toward volume production. Beyond process technology and PDKs, GF focuses on high-volume manufacturing capability and complete packaging solutions, helping customers bring photonics into data centers, supercomputers and communications applications.

Content

1. Drivers of silicon photonics adoption

• Data explosion: nearly every semiconductor product is driving more data generation. AI and supercomputing need higher-performance, lower-latency networking foundations.

• Idle GPU performance: because of data access bottlenecks, GPUs often sit waiting. Optical networking can improve data flow and raise GPU compute utilization.

• Energy efficiency: AI data centers consume enormous power, and lowering power per bit has become a shared industry goal.

2. GF's dual-track strategy: pluggables + CPO

GF emphasized that market demand for optical components runs in two main directions:

1. Pluggable transceivers

   • The mainstream solution today, already supporting 200G/lambda, with plans to advance to 400G/lambda in 2026.

   • Designs keep being optimized, removing or simplifying the DSP to cut power.

   • Still an important option for near-term data center connectivity.

2. Co-packaged optics (CPO)

   • A longer-term solution that tightly integrates the optical engine with the ASIC (such as a GPU or switch).

   • Places high demands on packaging, requiring solutions for thermal, density and fiber attach challenges.

   • GF offers multiple packaging options: integration directly on the ASIC interposer, on organic substrates, or using a silicon bridge.

GF is currently developing both pluggables and CPO as parallel technology tracks to meet market needs across generations and applications.

3. Core silicon photonics technology highlights

1. Modulators

   • Microring modulator (MRM): already meets IEEE specifications and supports 200G/lambda.

   • Ring-assisted MZM: combines an MZM with a ring structure, raising bandwidth to 85 GHz with an extinction ratio of 4.5–5 dB.

   • New materials: exploring lithium niobate (LN), BTO and polymers to support future >400G/lambda applications.

2. Filtering and wavelength multiplexing

   • Uses curvilinear lithography to make low-loss CWDM filters.

   • Lowers insertion loss in multi-wavelength systems.

3. Fiber coupling solutions

   • Offers grating couplers and edge couplers.

   • Introduces detachable fiber arrays: grooves are etched on chip to hold micro-optics, which then connect to multichannel fiber.

   • Supports high radix (multi-fiber arrays), raising data center connection density.

4. Manufacturing and ecosystem

• Volume manufacturing capability: GF has industrialized its silicon photonics process on 300mm silicon wafers (45CLO process), completing the full flow from wafer fabrication to packaging at its New York site in the US.

• Supply chain diversification: in addition to Taiwan's strong ecosystem, GF can offer a fully US-based manufacturing supply chain for customers who require "made entirely in the USA."

• EDA and PDK support: complete design tools and PDKs make it easy for customers to design their own devices or co-develop new ones.

5. Outlook

GF highlighted these future priorities:

1. Higher-speed transmission: advancing to 400G/lambda and beyond.

2. New material integration: bringing in BTO, LN and polymers to push past the limits of silicon.

3. Advanced packaging: continuing to strengthen detachable fiber connections and 3D packaging capabilities.

4. Volume production and reliability: moving silicon photonics from R&D to industrial-scale manufacturing.

GF's message was clear: now is the moment companies must set their optical strategy, or they will miss the huge market created by the data center and AI wave.

Conclusion

In its SEMICON 2025 talk, GlobalFoundries presented a complete silicon photonics technology and process roadmap:

• A dual-track strategy (pluggable + CPO) to meet the needs of different generations.

• An emphasis on high-volume capability and reliability, taking silicon photonics from small-scale R&D to industrialization.

• Active adoption of new materials and new packaging technologies to break through bandwidth and power bottlenecks.

GF isn't just offering a silicon photonics process; it aims to become a core pillar of the global photonics ecosystem. For GPU makers, switch vendors and data center operators, now is the best time to set an optical strategy.