Impact of optical transmission on multi-band OFDM ultra-wideband wireless system with fiber distribution

The performance of MB-OFDM UWB over fiber transmission system is investigated considering optical modulation and demodulation impact. Theoretical analysis of the effect of fiber dispersion, optical transmitter and optical receiver response on system performance is carried out considering amplitude and phase distortion. Experiments are conducted and verified by our theoretical analysis and good agreement is obtained. It is found that RF modulation index of ∼4% is optimum for optical transmitter with Mach-Zehnder modulator, and optical receiver with Chebyshev-II response is the best for MB-OFDM UWB over fiber. It is also found that high received optical power is required for transmission of MB-OFDM UWB signal over fiber.;The performance of MB-OFDM UWB over fiber transmission system is also studied considering the effect of in-band jammers such as WiMAX, WLAN MIMO, WLAN and marine radar. Experiments were performed to show the effect of fiber transmission under various interferer power levels. It is found that in-band interferers can cause severe degradation in system performance if certain interferer to UWB peak power ratio is not maintained.;Theoretical analysis of the effect of fiber chromatic dispersion induced laser phase to intensity noise or relative intensity noise (RIN) on system performance is carried out. Experiments are also conducted to verify our theoretical analysis. Simulation is also carried out to show the relationship between RIN and center frequency of UWB bands. It is found that the parameters like laser output power, laser linewidth and fiber dispersion that control RIN, will critically affect the overall performance of a UWB over fiber system.