High Dynamic Range Agile Radio over Fiber Transmitter’s Architectures for 5G/NR Applications

Abstract In this paper, we proposed a novel radio over fiber (RoF) transmitter architecture to achieve high dynamic range (DR) suitable for millimeter wave (mm-wave) applications, supported by simulation and experimental validations. The designed test benches achieved more than-41 dBc adjacent carrier leakage ratio (ACLR) for a fifth generation/new radio (5G/NR) signal of 100 MHz bandwidth, transmitted in the upper frequency range (FR2) at 28 GHz. The key for this achievement is the utilization of the electrical mixing with proper phase shift before optical modulation. The mixing of the local oscillator (LO) and the intermediate frequency (IF) signals in the electrical domain, reduces the unwanted beating between optical bands prior to the photo-detection stage, hence preventing photodetector saturation, which leads to higher optical-to-electrical conversion.