title: Digital predistortion for RSOAs as external modulators in radio over fiber systems.
abstract: Reflective semiconductor optical amplifiers (RSOAs) can be used as external modulators in radio over fiber (RoF) links due to their amplification and modulation characteristics and colorless property. The nonlinear distortion of RSOA, however, limits its dynamic range. In this paper we demonstrate digital predistortion (DPD) linearization techniques to improve the linearity of RSOA external modulators. 64 quadrature amplitude modulation (QAM) signals are utilized to extract the model parameters. The dynamic AM/AM and AM/PM characteristics and power spectral densities of the modulated signals from the RSOA are demonstrated without and with DPD. Experimental results show clearly that the nonlinear distortion of RSOA external modulators in RoF links can be compensated using DPD linearization techniques.
authors.affiliation: Instituto de Telecomunicações, Departamento Electrónica Telecomunicaçãoes e Inofrmática, Universidade de Aveiro, Campus Universitário de Santiago, Aveiro, Portugal.
authors.forename: Zhansheng
authors.initials: Z
authors.lastname: Liu
authors.forename: Manuel Alberto
authors.initials: MA
authors.lastname: Violas
authors.forename: Nuno Borges
authors.initials: NB
authors.lastname: Carvalho