Bidirectional colorless WDM-PON RoF system with large spurious free dynamic range

A bidirectional colorless wavelength-division-multiplexed passive optical network radio over fiber system with a large spurious-free dynamic range (SFDR) is proposed. By separating the unmodulated optical carrier from the polarization multiplexed optical signal in the optical network unit, upstream wavelength reuse is realized. By adjusting the angle and phase difference between the orthogonal optical polarization modes, third-order intermodulation distortion (IMD3) suppression of the downstream link is realized. The periodic power fading caused by dispersion in the system is solved through single sideband modulation. Experiments have verified the wavelength reuse effect of the upstream link. Compared with the traditional link based on a Mach-Zehnder modulator, the periodic power fading of the system is suppressed under different radio frequencies (RFs) and fiber lengths. The IMD3 of the downstream link is suppressed, and the SFDR is improved by more than 17 dB. Also, the proposed system is tested with a 16 quadrature amplitude modulation RF signal in the experiment, where a good adjacent channel power ratio and error vector magnitude of the system are obtained.