Digital predistortion technique for the compensation of nonlinear effects in radio over fiber links

Abstract

Due to their inherent capillary distribution properties, Radio over Fiber (RoF) systems are expected to play a major role within future fifth generation wireless networks. However, significant bounds on the technology usability are set by the nonlinear generation of spurious frequencies, which, in the case of RoF links exploiting Directly Modulated Lasers (DML), has the combined effect of laser chirp and optical fiber dispersion among its prevailing causes. In this paper, a signal digital predistortion system, which can lower these detrimental effects, is proposed in two different versions. A detailed description of its functional model is given, and its attractive features in terms of quality improvement of the received signal is illustrated.