Signal upconversion for a radio-over-fiber system with modulation types based on a frequency quadrupling technique

In this study, optical upconverted microwave frequency generation was experimentally demonstrated using a frequency quadrupling technique based on two types of baseband signal modulation in a radio-over-fiber (RoF) system. The measured results revealed that an error-free transmission could be achieved without causing the periodic power fading affect, and that clear eye diagrams were obtained after a 20-km transmission by using baseband/RF mixed-signal external modulation. The proposed method is a feasible technique for generating a 622 Mbps (1.25 Gbps)/15 GHz frequency quadrupling RoF signal without using narrow-band optical notch filters or sophisticated optical modulators. (c) 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1603-1610, 2014