High-speed optical modules (400G/800G/1.6T) serve as the core engines of data center and communication network traffic. These modules convert electrical signals into high-speed optical signals. Their internal PCBs, particularly the sections that interconnect driver chips and optical devices, place extremely stringent demands on the laminates used. The fundamental challenge is to achieve ultra-high-speed signal transmission within a very confined space while maintaining extremely low loss and absolute signal integrity. Material selection for this application has moved beyond ordinary “high-frequency” considerations into a domain where “ultra-low loss” and “exceptional process compatibility” are both critically important.

I. Core Performance Requirements: The Triple Challenge of Speed, Loss, and Precision

1. Ultra-Low Dielectric Loss is the Foundation: This is the most critical metric. To handle PAM4 electrical signals at 224Gbps and higher rates, the laminate’s Dissipation Factor (Df) must be below 0.005 at 10GHz, with top-tier solutions demanding values below 0.003. Any additional loss directly reduces the module’s transmission distance and performance margin.
2. Excellent Dimensional Stability and Heat Resistance: The interior of an optical module requires the precise alignment and soldering of micron-scale components like lasers, modulators, and detectors to their driver chips. This necessitates that the laminate exhibits minimal deformation (typically requiring dimensional stability within 0.05%) during multiple high-temperature reflow soldering cycles. This ensures placement accuracy and prevents failures in optical coupling.
3. Superior Copper Foil Surface Roughness: High-frequency signals travel along the copper foil surface due to the “skin effect.” Therefore, using Ultra Low Profile (ULP) copper foil is crucial. A smoother copper surface significantly reduces signal scattering and is a key physical method for lowering insertion loss.
4. Suitability for High-Density Interconnection (HDI): To minimize size, high-end optical modules commonly use substrate-like PCB (SLP) or advanced HDI designs. The laminate must reliably support fine processing techniques such as micro-vias and blind/buried vias, while ensuring the reliability of the via walls.

II. Mainstream Material Series and Evolution Direction

The optical module laminate market is dominated by several manufacturers with deep expertise in ultra-low loss technology. Their product lines continuously evolve, focusing on the balance between “loss” and “processability.”

1. Panasonic MEGTRON Series: This series is a gold standard for high-speed digital circuits. MEGTRON 6 was widely adopted during the 400G era. For next-generation 800G/1.6T designs, MEGTRON 7 and MEGTRON 8, with their even more extreme low-loss characteristics, are becoming the preferred choices for forward-looking designs.
2. Rogers High-Performance Laminates: Rogers is a key supplier. Certain models within its RO4000® series (e.g., RO4835™), known for their good low-loss properties and temperature stability, are often used in the RF driver sections of optical modules. For the core digital sections, laminates from its CuClad® series also provide ultra-low loss solutions.
3. Taiyo Technology TU Series: Taiyo is a vital material supplier in the optical module supply chain. Its TU-872 series, renowned for its excellent overall performance (low loss, high Tg, good dimensional stability), has secured a significant market share in mainstream global optical module designs, representing a mature and mass-production-verified choice.
4. Progress in Domestic Supply Solutions: Domestic manufacturers like Shengyi Technology and Wazam New Materials are advancing rapidly. For instance, Shengyi’s S7 series (e.g., S7439) and the more advanced S8 series products have completed validation and are being adopted by multiple major equipment and module manufacturers. Their performance meets 800G demands, positioning them as key pillars for supply chain security.

III. Practical Focus for Promotion and Material Selection

When engaging with the optical module industry, communicating detailed technical data is far more important than simply listing product names.

1. Present Complete “Loss vs. Frequency” Curves: Do not rely solely on a nominal Df value. It is essential to provide customers with measured insertion loss curves or Dk/Df versus frequency plots, typically from 1GHz to 40GHz or beyond. This demonstrates the material’s stable performance across the entire relevant frequency band.
2. Highlight “System-Level” Solution Capability: Laminate selection for optical modules is closely tied to copper foil choice, solder mask compatibility, and specific processing parameters. Your promotion should emphasize the comprehensive “material package” and supporting processing guidelines you can offer. This helps customers solve material selection and manufacturing process challenges holistically.
3. Provide a Comprehensive Reliability Data Package: Emphasize the material’s performance retention after accelerated aging tests, such as high temperature/high humidity (HTHH) and thermal cycling. Optical modules are designed for operational lifetimes exceeding 10 years, making the fundamental reliability of materials a critical factor in customer decision-making.
4. Understand and Address Localization Trends: Proactively engage with module design companies that are seeking supply chain diversification. Positioning your offering as a “performance-compliant, supply-stable, and responsive” domestic alternative can be a significant competitive advantage when vying against established international brands.

In summary, succeeding in the high-speed optical module market means becoming a materials science partner for customers who are pushing against electrical performance limits. Your value proposition extends beyond supplying a low-loss substrate; it encompasses delivering a complete, data-verified solution that ensures first-pass design success and reliable mass production for their most advanced products.