Modeling optoelectronic oscillators

We have developed a comprehensive simulation model for accurately studying the dynamics in optoelectronic oscillators (OEOs). Although the OEO is characterized by three widely separated time scales, our model requires neither long run times nor a large amount of memory storage. The model generalizes the Yao-Maleki model and includes all of the physical effects in the Yao-Maleki model as well as other physical effects that are needed to calculate important features of the OEO dynamics, such as the impact of the fast response time of the modulator on the phase noise power spectral density, the fluctuations of the OEO output due to the input noise, the cavity mode competition during the OEO start-tip, and temporal amplitude oscillations in steady state. We show that the absolute value of the phase noise is 2-3 dB lower than predicted by the Yao-Maleki model. The Yao-Maleki model does not take into account amplitude noise suppression due to the fast time response of the modulator, which accounts for this difference. We show that a single cavity mode oscillates in the OEO at steady state, and this mode is determined by the noise that is present when the OEO is turned on. When the small-signal open-loop gain is higher than 2.31, we show that the OEO amplitude oscillates in steady state. This temporal amplitude oscillation can be suppressed by using a narrow filter. Our simulation model, once extended to include flicker (1/f) noise and different amplifier and modulator designs, will enable its users to accurately design OEOs. (c) 2008 Optical Society of America