Adaptive Modulation for Open All-Photonics Networks

This paper presents an adaptive modulation method specifically for open all-photonics networks, which represent future optical transport architectures focusing on eliminating the need for optical-electrical-optical conversions. Unlike proprietary optical systems, open all-photonics networks lack built-in mechanisms for dynamically adjusting modulation formats in response to real-time changes in signal quality. This shortcoming makes them vulnerable to drops in performance due to variations in optical signal-to-noise ratio, attenuation, and link issues, especially in long-distance or multi-span settings. To address these challenges, we propose a method for real-time modulation reconfiguration based on telemetry inputs such as optical signal-to-noise ratio and forward error correction metrics. The proposed method is deployed and validated on a practical, 380 -kilometer open all-photonics network spanning from northern to southern Taiwan. The approach supports dynamic modulation adaptation across multi-vendor optical equipment using standardized, open network interfaces. Experimental results demonstrate that the proposed approach reduces the recovery time from several hours to less than two minutes under degraded OSNR conditions. These findings confirm the feasibility of implementing adaptive modulation in disaggregated photonic infrastructures and underscore the importance of real-world validation in the development of scalable and resilient all-photonics network systems.