Introducing Combined Effects of Filtering and ASE Noise in Optical Links Supposing Different Equalization Algorithms
Enrico Miotto, Andrea Rosso, Emanuele Virgillito, Stefano Straullu, Andrea Castoldi, Andrea Bovio, Francisco Martinez Rodriguez, Vittorio Curri
Published: 2025/4/24
Abstract
This paper presents a comprehensive analytical framework for evaluating filtering penalties in ASE-noise-limited coherent optical links. The model accounts for the cumulative effects of cascaded optical filters, amplifier-induced ASE noise, and transceiver noise, alongside digital equalization at the receiver. By developing a generalized channel representation, we derive closed-form expressions for signal-to-noise ratio degradation under various equalization strategies, including Zero-Forcing Equalizer, Minimum Mean Square Error Equalizer, and Fractionally Spaced Equalizer. These models capture the impact of colored noise resulting from linear filtering and provide both time and frequency-domain insights. The proposed framework is validated through experimental comparisons using accurately modeled optical filters, demonstrating close agreement between theory and practice and offering a robust foundation for system-level performance evaluation in metro-access networks.