A comparative analysis between different optical modulators of analog and digital radio over fiber (RoF) link for the next-generation networks

This paper highlights the analytical and simulative approach of Linearized Radio over Fiber (RoF) Link. In the proposed research article, we perform the comparison between mostly utilized optical modulators as: Mach-Zehnder modulator (MZM), dual-drive Mach-Zehnder modulator (DD-MZM), linear electrical absorption modulator (EAM) and phase modulator (PM)-based RoF link. These optical modulators are design based on analog photonic RoF link method. Optical simulator (OptSim), which is versatile commercial simulation software, is used to confirm and validate the proposed results. In the proposed model, we compared the fundamental to distortion component ratio (FDCR) of measured and evaluated electrical spectrums for all used optical modulators-based RoF link. The measured FDCR for used optical modulators as: MZM, DD-MZM, Linear EAM and PM is found as 36.41 dB, 43.50 dB, 13.0 dB and 21.9 dB, respectively. DD-MZM-based RoF link exhibits highest FDCR with measured value 43.50 dB, then all used optical modulator. It shows that the DD-MZM-based RoF link exhibits higher Linearization compared with others used optical modulators-based RoF link. We also proposed a comparatively analysis between MZM and DD-MZM-based Digitized RoF link for different fiber impairments from 2 to 40 km. The measured Q-factor has been found as 22.026 dB and 23.028 dB for MZM and DD-MZM-based Digitize RoF Link, respectively. DD-MZM-based digitized RoF link shows the enhanced eye pattern in terms of signal-to-noise ratio for used fiber impairments.