Radio Over Fiber Link And Performance Improvement

Radio over fiber (RoF) system is an enabling technology in Microwave Photonics, not just because it has the advantages of wide bandwidth and high immunity to eletro-magnetic interferences, but because, it simplies the configuration of base station and communication networking. These make it quite adaptable and promising in the fast development of communication and networking technology. However, RoF link needs electro-to-optical conversion and optical-to-electro conversion, which degrades the link performance and limits its developments.In this thesis, RoF links are investigated in three parts. First, RoF link model is analyzed. Then wavelength-division-multiplexing (WDM) RoF link is demonstrated, including its experimental configuration and implementation. Based on the RoF link model, the methods on RoF link performance improvement are discussed.In the link model part, two different ways are used to analyze the RoF link performance. The first one is based on the link and optical signal, but the second way originates from the equivalent ciucuit model of photonic devices under small signal. And these two methods have consistent results about RoF link and complement each other. For example, the second one discusses that the link performance is related with the device fabrication. Besides, the WDM technology and the implementation of WDM RoF link in our Microwave Photonics laboratory are introduced.Finally, the methods about how to improve the link performance are analyzed, including increasing the input optical power and carrier subtraction that can be realized through stimulated Brillouin scattering (SBS), low-biasing and optical filter. Both intensity modulation and phase modualtion are analzyed. Besides the theory analysis, the validity of these methods are verified through simulation and experiments.