Improving Performance of Higher-Order Codirectional Raman Amplifiers Using Phase-Modulated Signals -- Functional Principle

TL;DR

This paper discusses a method to improve the performance of third-order codirectional Raman amplifiers in submarine links by reducing phase shifts caused by pump power fluctuations using phase modulation.

Contribution

It introduces a novel approach to mitigate Kerr-induced phase shifts in phase-modulated signals within high-power Raman amplification systems.

Findings

Reduced phase noise in phase-modulated signals

Enhanced stability of submarine optical links

Improved amplifier performance under high pump power

Abstract

Existing unrepeatered submarine links are increasingly upgraded to the most advanced modulation format currently available for commercial applications. Quite often the use of third-order codirectional Raman amplifiers is necessary. Power fluctuations of the involved high-power pump induces phase shifts in phase modulated signals via the nonlinear Kerr effects. An approach for reducing the impact of this effect on system performance is explained in this document.