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:

Proprietary capacity-reach optimized transceivers that maximize channel capacity for any distance, including regional coverage 800G and short haul 1200G in 2023, and
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