Introduction: From 100G to 400G WDM/OTN

From the perspective of communication evolution, higher transmission speed has always been the central driving force of optical networks.
At present, 100G WDM/OTN represents the mainstream solution, and China has already deployed the world’s largest commercial 100G optical transmission network.

However, as network traffic continues to surge, this once-advanced architecture is gradually reaching its limits.
Therefore, the industry is now accelerating its transition toward 400G WDM/OTN, which has become the next strategic milestone.

The Bandwidth Challenge in the 5G and Cloud Era

With the commercial rollout of 5G, data traffic has grown at an unprecedented pace.
At the same time, emerging technologies such as cloud computing, big data, and AI are reshaping network usage patterns.

As a result, traditional 100G systems are increasingly under pressure.
Consequently, network operators and cloud service providers must look beyond incremental upgrades and adopt higher-capacity transmission technologies.

In this context, 400G WDM/OTN naturally comes into focus.

Why 400G WDM/OTN Becomes the Industry’s Only Path Forward

To effectively handle massive data aggregation, modern networks must transport large volumes of information from access layers to centralized cloud platforms.
Therefore, single-carrier coherent transmission above 100G—especially 200G and 400G—has become the preferred solution.

Compared with legacy architectures, 400G WDM/OTN delivers significantly higher spectral efficiency.
In addition, it reduces cost per transmitted bit while improving overall network scalability.

In other words, 400G is no longer an optional upgrade.
Instead, it has become a structural necessity for next-generation network construction.

Data Centers Drive the Rapid Adoption of 400G WDM/OTN

The rapid expansion of hyperscale data centers further accelerates this transition.
For example, leading cloud providers continue to increase their data processing capacity year after year.

As demand rises, data centers must interconnect thousands of servers using high-speed optical fibers and modules.
Accordingly, the evolution of data center rates typically follows a clear path:

10G → 40G → 100G → 400G

Therefore, It  has become the natural next step for data center interconnection and backbone networking.

Optical Modules and Ecosystem Expansion

With the market direction clearly established, manufacturers of optical devices and modules are rapidly increasing their investment in 400G technologies.
Meanwhile, industry players are racing to optimize modulation formats, DSP capabilities, and system-level integration.

As a result, the entire optical ecosystem is moving toward higher efficiency and stronger interoperability.
This trend clearly indicates that 400G WDM/OTN offers both broad commercial potential and long-term strategic value.

Conclusion: 400G WDM/OTN as the Foundation of Future Networks

In summary, the transition from 100G to 400G WDM/OTN is driven by real and measurable network demands.
As cloud computing, 5G, and data-intensive applications continue to expand, higher-capacity optical transmission becomes unavoidable.

Ultimately, 400G WDM/OTN is not just a technological upgrade.
Rather, it is the foundational infrastructure that will support the next decade of global digital growth.