Microwave-photonics iterative nonlinear gain model for optoelectronic oscillators

Abstract

The nonlinear dynamic behavior of optoelectronic oscillators (OEOs), which is important for the OEO based applications, is investigated in detail by a Microwave-photonics Iterative Nonlinear Gain (MING) model in this paper. We connect the oscillating processes with the trajectories of an iterated map based on a determined nonlinear mapping relation referred to as open-loop input to output amplitude mapping relation (IOAM). The results show that the envelope dynamic is determined by the slope of IOAM at a special point called fixed point. Linear features dominate the loop if the slope is relatively large, and the nonlinear features emerge and become increasingly significant with the decreasing of the slope. Linear features of homogeneity and monotonicity are gradually lost. Furthermore, OEO is even unstable when the slope is less than a general threshold value of −1. The behavior of OEO loops with the different slope values are discussed by simulations and are experimentally confirmed. Moreover, the proposed model also applies to the OEO with an externally injected microwave signal, the bifurcation phenomena caused by injected signal are experimentally evidenced.