Experiment Analysis of Nonlinear Indices in RFA Deployed Long-Haul CATV Transmission System

Erbium doped fiber amplifier (EDFA) is widely deployed in long-haul fiber CATV systems nowadays for its cost-effectiveness, ease for directly access, larger gain, higher saturated output power, and polarization insensitivity. However, EDFA would also bring serious nonlinear effect for such systems. In this paper, an idea that deploying Raman fiber amplifier (RFA) in long-haul CATV transmission link is proposed, its nonlinear property is studied via experiment, and its system performance is compared with EDFA deployed long-haul CATV system. Experiment analysis shows that by deploying RFA, the Carrier-to-Noise Ratio (CNR) of system would be deteriorated on some level, but system nonlinear indices such as Composite Second Order (CSO) distortion and Composite Triple Beat (CTB) distortion can be effectively improved.