Multiplexing of RF-assisted fiber ring resonators based on phase-shift amplification

Abstract

The multiplexing of fiber ring resonators (FRRs) for no crosstalk loss sensing is proposed and demonstrated experimentally. The difference between the parallel and series FRRs is theoretically elaborated to determine the multiplexing scheme. The frequency response properties of the cascaded FRRs at distinct radio frequency (RF) working points are compared and analyzed. The optical carrier-based microwave interferometry system is implemented to verify the numerical investigation and exhibit the multiplexing of phase-shift based demodulation at diverse RF working points. Enhanced by the phase-shift amplification and the series configuration, each FRR can be independently demodulated by recording the phase of frequency response at the specific RF working point. The experimental results indicate that the sensitivity of transmittance reaches −0.341 rad with the advantage of robustness and immunity to power fluctuation. Owing to the prominent contribution of insensitive points and the series strategy, the crosstalk of multiplexing for loss sensing between two FRRs is eliminated virtually, which matches well with the theory. The proposed scheme provides an innovative approach for multiplexing the phase-based FRRs sensors without additional expenditure.