Stabilization concept for maintaining maximum suppression of the undesired sideband in a radio-over-fiber link using a single add/drop micro-ring resonator

Abstract

This paper proposes a solution to the stability problems of a radio-frequency-over-fiber (RFoF) link featuring an add/drop micro-ring resonator (MRR) to combat the unwanted phenomenon of chromatic-dispersion-induced RF power fading by introducing an optical single-sideband signal. The temperature dependence of the silicon-on-insulator photonic integrated circuit (PIC) accommodating the MRR results in a resonance drift, corrupting the initially configured optimal alignment of the resonant dip and the undesired sideband. The proposed stabilization concept introduces a feedback-control system employing the otherwise unused drop port of the MRR to provide the so-called process variable to the control system. The objective of this control system is to maintain the maximum optical power at the drop port through tuning the laser (carrier) wavelength.