Training large language models with trillions of parameters requires moving petabytes of data between thousands of GPUs. Traditional copper-based electrical interconnects are hitting fundamental bandwidth and power consumption limits, creating a critical bottleneck for AI infrastructure.

The Electrical Interconnect Wall

Current high-speed electrical interconnects face several challenges at scale:

- Signal Integrity: Copper traces suffer from attenuation and crosstalk at high frequencies

- Power Consumption: Electrical SerDes (serializer/deserializer) circuits consume significant power

- Reach Limitations: Maintaining signal quality over distances beyond a few meters becomes prohibitively expensive

Optical Solutions

Optical interconnects use light instead of electricity to transmit data, offering transformative advantages:

Silicon Photonics

Integrating optical components directly on silicon chips enables high-bandwidth, low-power data transmission. Intel, Cisco, and startups like Ayar Labs are commercializing silicon photonics solutions.

Co-Packaged Optics

Placing optical transceivers directly in the same package as switch ASICs eliminates electrical bottlenecks and reduces power consumption by up to 50%.

Linear Drive Optics

New modulation techniques allow direct laser modulation without power-hungry DSP, dramatically reducing power per bit transmitted.

Performance Impact

Early deployments show impressive results:

- Bandwidth: 1.6 Tbps per fiber vs 400 Gbps for electrical

- Power Efficiency: 5 pJ/bit vs 15 pJ/bit for electrical at equivalent speeds

- Latency: Sub-100ns for rack-to-rack communication

Industry Momentum

Major infrastructure providers are accelerating optical adoption:

- Broadcom: Shipping co-packaged optics for hyperscale data centers

- NVIDIA: Integrating optical interconnects in next-generation DGX systems

- Amazon: Deploying custom optical solutions in AWS infrastructure

The shift to optical interconnects is not just an incremental improvement—it's a fundamental enabler for the next generation of AI systems, allowing model sizes and training speeds that would be impossible with electrical interconnects alone.