Theoretical Performance Evaluation of Spurious- Tone Suppression of a Multi-Loop Optoelectronic Oscillator Based on Closed-Loop Response Analysis

Abstract

We theoretically evaluate the performance of spurious-tone suppression of a multi-loop optoelectronic oscillators (MOEO) based on closed-loop analysis. Spurious tones are unwanted oscillation signals due to the cavity effect of long-length optical fiber and the severe drawbacks of optoelectronic oscillator (OEO). The spurious tones can be suppressed using the MOEO configuration with two controllable loop parameters of length and power ratios between multiple loops. We propose the method of closed-loop analysis to accurately extract the loop parameters and to increase spurious-tone suppression ratio (SSR). We successfully evaluated the MOEO performances with various loop-power ratios and achieved an SSR of 86 dB with a phase noise of -115 dBc/Hz at 10 kHz offset for a triple-loop OEO configuration by extracting the optimum power ratio of 0.332:0.131:0.537.