Design, Acceptance and Capacity of Subsea Open Cables

This paper will discuss the collaboratively formed cross-industry Open Cables concept for characterizing optical performance of undersea cables with the intent of assessing and understanding their capacity potential. The paper proposes definitions of two critical nonlinear and linear performance metrics for Open Cables: GSNR (Gaussian Signal to Noise Ratio) and SNRASE (Signal to Noise Ratio Amplified Spontaneous Emission), including effects such as Guided Acoustic Wave Brillouin Scattering (GAWBS) and signal droop. Measurement methodologies for these metrics are proposed, with considerations for limitations and impact of the test conditions and characteristics of the transponders used. Expanded definitions are offered to enable variable baud-rate transponders to be used for measurement, with considerations for scaling of SNR values. Considerations for using these metrics for capacity assessment and applying these techniques to concatenated multi-segment systems are introduced. Recommendations on key parameters for system specification, system characterization and proposals for SNR-based performance budgeting tables are also discussed as foundational elements to enabling accurate estimation of the capacity potential of a subsea Open Cable.

• Networking