Time-Domain Dynamics and Stability Analysis of Optoelectronic Oscillators Based on Whispering-Gallery Mode Resonators

Optoelectronic oscillators (OEOs) are microwave photonics systems intended to generate ultrastable radio-frequency signals with unprecedented phase noise performance for aerospace and communication engineering applications. They had originally been introduced in a configuration where the energy storage element was a fiber delay line. However, recent research in view of size and power consumption optimization has led to novel configurations where this fiber delay line is replaced by an ultrahigh Q whispering-gallery mode (WGM) resonator. So far, there has been no theoretical framework enabling to understand the dynamical behavior of these new architectures of OEOs. In this paper, we propose for the first time a deterministic time-domain model to investigate the dynamics of these OEOs based on WGM resonators. This model enables us to perform the stability analysis of the microwave oscillations, and to determine rigorously their range of stability as the loop gain is varied. After building the model, we perform a full stability analysis of the various stationary solutions for the microwave output. We then perform extensive numerical simulations, which are in complete agreement with the stability analysis. The theoretical analysis is also found to be in excellent agreement with our experimental measurements.