O-Band Incoherent Technology: The Optimal Choice for Scale-Across Computing Networks

SHENZHEN, China - May 26, 2026 - PRLog -- I. Background: Layered Requirements of Computing Networks

With the deployment of large-scale AI training and inference clusters, computing interconnect networks are developing a distinct layered architecture:

These two types of networks have fundamentally different requirements for optical modules. Long-distance computing networks must use coherent communication, whereas Scale Across short-to-medium range networks have absolutely no need for coherent solutions—the additional cost, power consumption, and latency introduced by coherent systems are purely burdensome in this scenario.

II. Why Does Scale Across Choose O-Band Incoherent Solutions?

O-Band (1260–1360 nm) offers three key advantages in short-to-medium range transmission:

• Zero-Dispersion Window: O-Band operates near the zero-dispersion point of optical fiber—no dispersion compensation is needed, signal integrity is excellent, and it accommodates high-order modulation formats like PAM4 without DSP dispersion equalization overhead.
• Low Latency: The incoherent architecture eliminates the processing delay of coherent DSP, achieving extremely low end-to-end latency—critical for collective communication operations like All-Reduce in AI training.
• Most Economical System Cost: No local oscillator laser, 90° optical hybrid, or complex DSP required; silicon photonics solutions are sufficient, and BOM cost is substantially lower than coherent solutions.

In Scale Across scenarios, O-Band incoherent solutions provide the optimal cost-latency-power triangle balance.

III. Current Product Coverage: Up to 800G Without Obstacles

The current incoherent solution based on single-wavelength 100G O-Band can fully cover up to 800G speeds. In the future, the 800G solution can be built on the proven single-channel 200G PAM4, with low technical risk and high system completeness.

IV. 1.6T Scale Across: Evaluation of Three Technical Pathways

When evolving toward 1.6T, there are three viable pathways, each with different technology maturity and engineering constraints:

Path 1: 1.6T PSM DWDM4 (Single-Wave 400G PAM4, Silicon Photonics Modulation)

Path 2: 1.6T 2×PSM DWDM4 (Single-Wave 200G PAM4, Silicon Photonics Modulation)

Path 3: 1.6T NPO 2×(PSM DWDM4) (Single-Wave 200G PAM4) ✓ Recommended

VI. Conclusion

The fundamental requirements of Scale Across computing networks are: low latency, low cost, high density, and easy operation and maintenance. In short-to-medium range computing interconnect scenarios, the system complexity introduced by coherent communication is completely unnecessary, and O-Band incoherent solutions naturally align with these requirements.

• O-Band incoherent 400G and 800G PSM DWDM4 solutions are technically mature and ready for large-scale deployment.
• O-Band incoherent 1.6T DWDM can be achieved through design innovation.
• https://www.gigalight.com/solutions-community-10321.html