Optimization of signal quality at receiver end by spectral inversion in 40 Gb/s direct-detection optical fiber transmission systems

The received optical signal quality of 40 Gb/s data rate direct-detection transmission system can be substantially improved by a system composed mainly with optical devices at the end of the last span of the transmission link. The system is mainly composed of a spectral inversion module (optical phase conjugation) followed by a high nonlinear fiber (HNLF) at the receiver end. The simulation and experimental results demonstrate effective signal waveform distortion compensation in a 40 Gb/s long-haul single channel intensity and phase modulated optical transmission systems.