Augmented space signal detection method for IM/DD optical communication systems

The demand for high-speed data transmission has increased rapidly in data centers, leading to advanced optical communication technology innovation. At high modulation speed, severe linear and nonlinear signal distortions degrade the link performance. In order to increase the transmission capacity, a robust signal detection method based on quadratic discrimination in augmented space (QDAS) is proposed for high-speed intensity modulation and direct detection (IM/DD) optical communication systems. By projecting along the feature vector initially obtained by the objective function following the generalized Rayleigh quotient, signals with different features can be separated in augmented space. Subsequently, decision optimization is achieved through a quadratic discriminant model. Experimental verification is performed based on the 120 Gbps PAM8-modulated vertical-cavity surface-emitting laser (VCSEL) multimode fiber (MMF) optical link (100 m). The results show that, compared with the traditional Volterra nonlinear equalizer (VNLE), the proposed QDAS detection method shows improved and robust bit error ratio (BER) performance with the same complexity. (C) 2022 Optica Publishing Group