Square-wave optoelectronic oscillators: Effects of noise in bit generators

Optoelectronic oscillators delivering optical square waves may potentially serve as sources of optical or microwave bits. Noise analysis and prediction of eye diagrams and various figures of merit can involve intensive numerical simulation specific to a given problem at hand. Here we present an analytically tractable model of the effects of amplitude noise and timing jitter on the use of such a square-wave generator as an optical binary bit train. The approach depends on a small number of empirical parameters characterizing the temporal correlations of noise in the system. We compute in closed form the time-averaged signal, autocorrelation function, power spectral density, eye diagram, quality factor, bit-error rate, and Allan variance. While the model exploits simplification as the cost of tractability, the availability of such a model is expected to be of interest more broadly in digital communications to provide a simple tool for analysis and characterization.