Analysis of mach zehnder modulator response to fiber dispersion in radio over fiber at 60 GHz for multigigabit wireless transmission

Abstract

Radio over fiber (RoF) at 60 GHz band is a promising technology for future wireless multi-gigabit transmission in personal, local and wide area networks. With coherent optical orthogonal frequency division multiplexing (CO-OFDM) technique adopted in RoF, to achieve multigigabit speed of transmission, the fiber dispersive effect on the modulated output of Mach Zehnder modulator (MZM) of the RoF system play a critical role in limiting the performance of the system. This paper briefly reviews the multi-gigabit wireless transmission at 60 GHz that indicates the need for radio over fiber architecture, followed by the analysis of MZM response in a dispersive fiber it leads to the power degradation of the transmitted signal over distance. The results for varied bias voltages (i.e., for large and small chirp) at finite extinction ratio indicate that the power degradation due to fiber dispersion at any distance of the fiber can be controlled by appropriate choice of the chirp. Furthermore the results indicate that for a personal and local area networks at 60 GHz, which extends up to few hundred meters the power degradation due to fiber dispersion, can be reduced significantly by varying the chirp without any additional dispersion compensation technique.