ROF Technologies Applied for Cellular and Wireless Systems

Two kinds of ROF systems are presented. First kind is applied for current cellular systems in Japan. Indoor service area is covered by ROF access units which are connected to an base ROF unit by optical fiber cables. The features are the compactness of the equipment and triple bands operation. Second kind adopts new ROF technologies. It can be used in the various situation, even usual ROF systems are not applicable, since it operates without electric power supply. Key technologies are impedance matching between RF circuits and E/O devices, ultra low power consumption RF amplifier, and optical power transmission. Experiments were carried out at 2.45 GHz band. E/O device conversion loss was reduced around 7 dB by 3-stub type impedance tuner. Electric power of 26.5 mW was obtained at the base station. By using an RF amplifier, no degradation was observed for reverse link transmission.