Data Center Evolution Driving Nx400G Lanes

February 13th, 2024

I recently spoke at the North American Network Operators’ Group (NANOG 89) conference in San Diego, CA. My presentation titled “Pushing Nx400G Further.” I focused on data centers and the growing traffic driving the need to build optical networks in multiples of 400G lanes – 400G/800G/1200G and so on – to transport this ever-increasing capacity demand.

In my presentation I illustrate how the industry is leveraging progress in DSP technology to create two complementary types of 0dBm transceiver solutions to meet different needs:

  1. Proprietary capacity-reach optimized transceivers that maximize channel capacity for any distance, including regional coverage 800G and short haul 1200G in 2023, and
  2. Standard cost-power optimized transceivers that provide strong enough performance for most metro applications, including 400G in 2023 and 800G in 2024.

I explain in detail on how these solutions can operate together on the same fiber using a rational 75GHz/150GHz channel plan. Here is an outline of my presentation. You can also watch the complete presentation on YouTube.


Cost and power optimization

  • Efficiency
  • Interoperability

Stay in Your “Lane”

  • 100Gbe traditional
  • 400Gbe lanes and client interfaces
  • 800Gbe right around the corner

How do we bundle all these “lanes” across these interfaces for higher performance: reach, density and capacity.

Two Trends

  • IP over DWDM
  • IP over Optical Transport

Use Cases

  • Capacity and reach optimized capabilities.
    • 1.2T with 1.6T in the future
    • 1500 – 2000 km with 800G
    • Ultra long haul with 400G
  • Cost and power optimization
    • Efficiency
    • Interoperability

Baud Rate Key to Practical Nx400 Lanes

Engineering Challenges and Solutions Necessary

  • Line Rate – 400G, 800G, 1200G
  • Modulation Reach is inversely proportional to modulation density
  • Baud Rate – Not physics limited. Allows you to take advantage of new technologies

Modulation Targets

  • Schemes
  • Bits
  • Distances
  • Applications

Transceiver Evolution

  • Capacity-Reach Optimized
  • Cost-Power Optimized

What is Around the Corner        

  • Line rate and Baud Rate capability predictions
  • 400G in 2023
  • 800G in 2024
  • 250Gbaud ?
  • Spectrum Planning – Waste Not. Want Not.

Watch the complete presentation on YouTube

Please see these additional resources

5nm-140Gbaud Wavelengths - 400G to 1.2T

Apollo Optical Networking – Programmable and open optical networks

High Density Low Power Consumption Optical Networking