A Theoretical and Experimental Study of Injection-Locking and Injection-Pulling for Optoelectronic Oscillators Under Radio Frequency Signal Injection

Abstract

This article presents a detailed study of injection-locking characteristics of a single-loop optoelectronic oscillator (OEO) under strong radio frequency (RF) signal injection. We provide formulas for the steady-state phase-angle after locking, and the locking time for a higher level of a locking signal, considering only the phase perturbation. We also provide a compact expression for the main spectrum components of the pulled OEO in terms of the beat frequency, which is useful to evaluate and quantify the injection-pulling effects in the OEO. The experimental results provide partial support to the conclusion of the analysis. The analytical and experimental results are presented in design curves, which can be used to determine the required properties of an injection-locked OEO for a specific performance of the oscillator.