Phase to intensity modulation and fading compensation using a single ring resonator for radio-over-fiber links

Abstract

In this study, we present a simulation-based analysis of radio-over-fiber (ROF) transmission links incorporating both phase modulation (PM) and a single ring resonator (RR) as the modulation transformer (MT). This configuration offers cost-effectiveness, enhanced operational stability, facile reconfiguration, and heightened robustness. The optimization of the RR involves a comprehensive adjustment of the power coupler coupling coefficient (k) and the roundtrip optical phase shift (φ) to attain superior characteristics in terms of power output, bandwidth, dispersion, and nonlinearity, individually. The simulation encompasses the transmission of diverse data formats, including QPSK, 16QAM, and 16QAM-based OFDM, modulated by the PM-RR system. The results reveal a 0.25 dB improvement in nonlinearity tolerance, increased power, and superior fading mitigation compared to the conventional intensity modulation (IM) approach. Furthermore, through careful tuning of the phase response, the Q factor of the PM-RR system exhibits an enhancement exceeding 40% over a 100 km fiber length when compared to the Mach-Zehnder modulator (MZM) system.