Multi-Wavelength Optical Single-Sideband Modulated WDM Radio-over-Fiber Systems by Employing a Twin-Core Fiber

Multi-wavelength optical single-sideband (OSSB) modulation for wavelength-division-multiplexed radio-over-fiber (WDM-RoF) systems using a twin-core fiber (TCF) is proposed and demonstrated in this study. A TCF shows a periodic transmission spectrum due to the inherent coupling between the cores. Optical double-sideband (ODSB) signals generated by a Mach–Zehnder modulator pass through the TCF to realize multi-wavelenth OSSB modulation for WDM-RoF systems. Due to the negative slope of the TCF transmission spectrum, the upper-sideband experiences higher attenuation than the lower-sideband for each wavelength channel. In addition, the optical carrier-to-sideband ratio (OCSR) also can be optimized, simultaneously, which can enhance the transmission performance of RoF links. The performance analysis of the proposal is carried out via simulations, results show that the receiver sensitivity is improved 10.35 dB with OCSR reducing from 12.48 to 6.89 dB. The RF power fluctuation also can be optimized by employing the TCF to suppress the upper-sidebnd (or lower-sideband).