| As the development of informational society, the increasing demand for wireless video-based interactive and multimedia data services explains why the radio-over-fiber (ROF) is a promising candidate to provide multi-gigabit-per-second wireless services. While attempting to generate and transmit millimeter-wave (MMW) signals in a wireless system costs effectively and increases the spectral efficiency to facilitate multi-gigabit-per-second services, so this work needs radio-over-fiber (ROF) systems based on optical frequency multiplication to reduce the bandwidth requirement of optical transmitters. Nowadays, ROF technology focuses on the generation of millimeter-wave signal, long distance transmission and demodulation technology more and more. Among them, the MMW signal generation, transmission and demodulation are the key ROF technologies. How to generate a high frequency MMW signal and achieve long distance optical transmission becomes a hot topic in ROF technique.In this paper, firstly, I introduce the background, features and research status of ROF technology at home and abroad. Several photonic millimeter-wave frequency multiplication technology have been considered.External modulation is an attractive solution for high-frequency and frequency-tunable millimeter-wave signal generation due to its simplicity and stability, in addition to the large frequency tenability and high spectral purity of the generated millimeter-wave signal.I also compare the difference between double sideband modulation (DSB). single sideband modulation (SSB) and optical carrier suppression (OCS) of external modulation technology.Secondly, a generalized approach to achieving microwave frequency-multiplying generation based on external modulation using a Dual-parallel Mach-Zehnder Modulator (DPMZM) is firstly presented. A theoretical analysis is developed, and the operating conditions are given to achieve frequency quadrupling, sextupling. and octupling Millimeter-wave generation. The impact of the finite extinction ratio (MR) and modulation index of DPMZM on the generated millimeter-wave signal is also evaluatedfinally, a scheme for photonic generation of frequency quadrupling millimeter-wave signal without using a wideband microwave phase shifter and an optical filter is proposed. The impact of the finite extinction ratio (HR) and modulation index of DPMZM on the generated millimeter-wave signal is also evaluated. The simulations based on Optisystem for the link of ROf transmission system are built, a good performance of the hybrid MMW signal is observed by the eye and constellation. A conclusion and prospect of this paper are given in the final chapter. |
PDF Full Text Request