Radio-over-Fiber (RoF) technology has been developed since the late 20th century and has been used efficiently in a range of applications for communication system. RoF system refers to the radio signals which are modulated with optical signal and transmitted over optical fiber link from Central Office (CO) to the Remote Nodes (RNs). In this work, several RoF systems have been designed and simulated. These systems were compared with each other to check for better performance. These systems are presented as follows: The first system is RoF with Quadrature Phase Shift Keying (QPSK), 16-Quadrature Amplitude Modulation (16-QAM), and 64-QAM schemes with and without OFDM technique. The second system is the RoF with QPSK and 16-QAM schemes with Digital Signal Processing (DSP) unit in the receiver side. The third system is RoF system with two multiplexing techniques, 8� Gbps WDM-RoF system and 4�Gbps SCM-RoF system, have been simulated with 4-QAM-OFDM, 16-QAM-OFDM and 64-QAM-OFDM schemes. The fourth system was to combine the techniques of wavelength division multiplexing (WDM) and subcarrier multiplexing (SCM) to increase the capacity of the system by 20�Gbps data rate.