High-performance RF signals transmission in SCM/WDMA radio-on-fiber bus link using optical FM method in presence of optical beat interference

In the near future, various wireless services such as a wireless local area network and an intelligent home appliance will be widely used at home or office. To connect among many radio base stations such as a home or office network, a subcarrier multiplexing/wavelength division multiple access (SCM/WDMA) radio-on-fiber (RoF) bus link is excellent in simplicity and flexibility. However, a degradation of RF transmission performance due to optical beat interference (OBI) is a severe problem. This paper proposes the reduction method of OBI using an optical frequency modulation (OFM) method in the SCM/WDMA RoF bus and theoretically analyzes the availability of this proposed method. Using the OFM method, the power spectral density of the OBI can be reduced and the improvement of carrier power to noise power ratio before FM demodulation using the proposed method is obtained at approximately 4 and 9 dB compared to the intensity modulation/direct detection method when FM index /spl beta//sub FM/ is 1 and 10, respectively.