Active Optical Cables: Rebuilding the Data Center Interconnect Foundation for the AI and Cloud Era

Introduction: When Copper Hits Physical Limits, Optical Interconnects Take Center Stage

AI model training, high-performance computing clusters, and large-scale cloud services—these core engines driving the digital economy are placing unprecedented demands on bandwidth and latency within data center networks. In short-reach interconnect scenarios—both intra-rack and across adjacent racks—the physical limitations of traditional passive copper cables (DAC) are becoming increasingly apparent: transmission distance is severely constrained (typically no more than 5–7 meters), and high-density deployments face challenges such as bulkiness and susceptibility to electromagnetic interference. It is in this context that Active Optical Cables, with their unique positioning that combines the advantages of optical fiber transmission with plug-and-play convenience, are evolving from an alternative option to a core component for building efficient, reliable communication networks.

What Are Active Optical Cables?

An Active Optical Cable is an interconnect solution that highly integrates optical fiber transmission with optoelectronic conversion technology. Unlike copper cables that transmit electrical signals directly, AOCs integrate optoelectronic conversion engines inside the connectors at both ends—converting electrical signals to optical signals at the transmitting end, transmitting them through optical fiber, and converting them back to electrical signals at the receiving end. This "electrical-optical-electrical" conversion process gives AOCs the combined benefits of optical fiber—long reach, high bandwidth, and immunity to electromagnetic interference—along with the ease of deployment characteristic of copper cables. Today, AOC products are widely deployed across multiple protocol interfaces, including InfiniBand, Ethernet, and DisplayPort.

Market Drivers: AI Compute Demand Ignites the High-Speed Interconnect Market

Market data confirms the strategic value of this technology. According to industry analysis, the global active optical cable market is projected to grow from approximately $3.6 billion in 2024 to nearly $7.8 billion by 2030, representing a compound annual growth rate of 14.2%. In the Chinese market alone, the AOC market size reached approximately RMB 12.056 billion in 2025, with growth rates significantly exceeding the global average. At a more macro level, LightCounting data indicates that Q1 2026 sales of optical transceivers and active optical cables reached approximately $10 billion, a year-over-year increase of over 90%, demonstrating an exponential growth trajectory.

The direct driver of this growth is the massive capital expenditure by hyperscale data centers to support AI training and inference workloads. Data centers, as the largest application scenario for AOCs, account for approximately 40% of global market demand.

Technology Frontiers: From 800G Proliferation to the MicroLED Revolution

1. 800G and the HYBRID Architecture Breakthrough

To meet the stringent low-power, low-latency requirements of AI clusters, the industry is moving beyond traditional DSP-based architectures. A notable example is the "half-DSP" HYBRID design proposed by Gigalight. By retaining DSP functionality on only half the channels at either the transmit or receive end, this solution achieves a 20–30% reduction in power consumption, cuts link latency by nearly half, and optimizes costs by approximately 21%. This technology already supports both multimode VCSEL and single-mode silicon photonics platforms, making it suitable for 800G and even 1.6T data center and AI interconnect scenarios.

2. MicroLED Light Sources: A Technological Leap for Next-Generation AOCs

An even more revolutionary breakthrough is emerging from innovations in light source technology. MediaTek, in collaboration with Microsoft Research and other partners, has successfully developed a next-generation active optical cable based on miniaturized MicroLED light sources. By replacing traditional "narrow-band, high-speed" laser channels with hundreds of parallel, "broadband, low-speed" MicroLED channels, this technology achieves multiple breakthroughs:

• Energy Efficiency Leap: By directly modulating MicroLEDs and eliminating complex DSP circuitry, power consumption is reduced by up to 50% compared to conventional VCSEL-based AOCs.

• Copper-Grade Reliability: The simple structure and temperature insensitivity of MicroLEDs deliver link reliability comparable to copper cables—a significant improvement, as traditional laser-based optical cables can have failure rates up to 100 times higher than copper.

• Transmission Distance and Scalability: This approach maintains high reliability while vastly exceeding copper's transmission distance, and it can scale to 800Gbps and beyond within standard QSFP/OSFP form factors. Commercialization is expected by late 2027.

AOC vs. DAC: How to Make the Right Technology Choice?

In actual data center deployments, AOCs and passive copper cables each have their own applicable boundaries. Understanding the differences between them is key to making sound technology decisions:

In short, for very short distances (<5 meters) where cost sensitivity is paramount, DAC remains the cost-effective choice for intra-rack connections. However, for scenarios that require crossing racks, resisting interference, and supporting flexible cabling, AOC's comprehensive performance advantages make it the superior solution.

Conclusion

In an era where AI compute demand is growing exponentially and data center architectures are evolving toward hyperscale, active optical cables have transcended their role as mere connecting cables to become strategic infrastructure components that determine overall system energy efficiency and performance. From the power optimizations of HYBRID architectures to the reliability revolution of MicroLED light sources, AOC technology continues to push beyond the physical limits of traditional copper and laser-based solutions. For decision-makers planning or upgrading data centers, fully understanding and leveraging AOC technology will be a critical step toward building high-performance, highly reliable, and energy-efficient networks for the future.