High bit rate optical transmission using midspan spectral inversion

Abstract

The problem of the phase noise generated by nonlinear effects and chromatic dispersion can limit the transmission distance and the bit rate for phase-shift-keying modulation formats. In this paper, the compensation of the nonlinear and linear effects by a midspan optical phase conjugation (OPC) is studied. First, we show the impacts of chromatic dispersion in an OD8PSK systems (Optical Differential 8-Level Phase-Shift Keying), then a long-haul differential 8-Level Phase-Shift Keying (OD8PSK) transmission simulation is studied in order to compare both the performance of the dispersion compensating fiber (DCF) and the midspan optical phase conjugation. OPC allow to obtain a best recovered of transmitted information especially when compared to a «conventional» transmission system; the latter uses dispersion compensating fiber (DCF). OPC performs better even if we increase the bit rate and the distance.

Key words: alternative modulation formats; Optical Differential 8-Level Phase-Shift Keying (OD8PSK); dispersion compensation; fiber optics communications; nonlinear phase noise; optical phase conjugation; spectral inversion.