NTT has successfully integrated, for the first time in the world, an in-service, end-to-end optical network visualization into a coherent DSP chip.
The function operates using only a receiver-side pluggable transceiver without dedicated measurement equipment or service interruption. The technology enables continuous end-to-end visibility into optical networks supporting the AI era, significantly improving network operations and maintenance efficiency.
Background
In recent years, rapid growth in AI demand has accelerated the expansion of both the capacity and geographic scale of inter-data-center optical networks and backbone optical networks. IOWN APN (All-Photonics Network) (*1), promoted by the NTT Group, represents next-generation infrastructure supporting this trend by leveraging photonics-electronics convergence device technology (*2) to achieve high-capacity, low-latency, and low-power communications. As high-capacity optical networks continue to expand, the importance of stable network operation has become increasingly critical.
To ensure stable operation of optical networks, it is essential to monitor optical signal power across the entire network and quickly detect and identify locations with abnormal loss. Conventionally, such monitoring required dedicated measurement equipment such as OTDR (Optical Time Domain Reflectometer) (*3), resulting in substantial operational and maintenance costs and making continuous end-to-end monitoring during live communication difficult.
To address this challenge, NTT has previously developed a technology capable of visualizing optical signal power across the entire optical network using only communication signals received by optical transceivers, without relying on dedicated measurement equipment [2,3,4]. However, because the technology required enormous computational resources, previous demonstrations were limited to proof-of-concept experiments using external computing systems. Widespread deployment in practical optical networks therefore required implementation within commercial optical transceivers.
Research Results
In this research, NTT integrated an unprecedented function of visualizing the entire optical network during live communication into a coherent DSP chip [5] (*4) inside an optical transceiver, and successful operation was demonstrated (Figure 1).
A newly developed proprietary technology reduced the computational processing required for visualization to 1/100 of conventional methods, enabling implementation in coherent DSPs and compact optical transceivers, where power consumption and footprint are tightly constrained. As a result, the world's first optical transceiver capable of locating anomalies within an optical network was realized.
Measurement results obtained using the proposed technology showed close agreement with those from dedicated equipment (OTDR), confirming that the technology provides sufficient accuracy for identifying abnormal locations.
Experiment
NTT implemented the network visualization technology in a coherent DSP chip [5] developed by NTT Innovative Devices Corporation (Figure 2). Using a compact pluggable optical transceiver equipped with the DSP (OSFP: Octal Small Form Factor Pluggable) (*5), the technology successfully demonstrated the ability to locate multiple optical power anomalies across optical networks spanning up to 1,005 km by simply receiving and processing standard-compliant optical signals (800ZR+/400ZR+ (*6)) (Figure 1).
The technology was also confirmed to operate properly when receiving optical signals from transceivers manufactured by other vendors, demonstrating applicability to real-world optical network environments, including multi-vendor deployments. In addition, the study confirmed that the technology does not affect communication quality or power consumption during measurement, demonstrating the feasibility of distributed monitoring across the entire optical network while communication services remain active.
Future Outlook
This achievement marks the world's first integration of an end-to-end network visualization into a communications DSP chip and compact optical transceiver — a breakthrough capability not available in conventional optical transceivers. By enabling optical transceivers to autonomously detect network anomalies, the technology is expected to significantly improve the efficiency of optical network operation and maintenance.
NTT will continue advancing implementation of the technology in optical networks, including IOWN APN, and accelerate research and development toward continuous monitoring and autonomous operation of high-capacity optical networks supporting the AI era.
