Study on the performance of injection-locked single-loop optoelectronic oscillators in presence of additive white Gaussian noise

Abstract This paper presents a detailed study on the synchronization characteristics of a single-loop optoelectronic oscillator (OEO) under the influence of radiofrequency (RF) signal, which is contaminated with additive white Gaussian noise (AWGN). The influence of the AWGN on the performance of the injection-locked optoelectronic oscillator (IL-OEO) is investigated in terms of the probability of losing lock, average beat frequency, and frequency of skipping cycles. Fokker–Planck technique is utilized to derive the expression for the probability density function (PDF) of the phase difference between the injection RF signal and the OEO output signal. The probability of losing lock on the two sides of the IL-OEO oscillation frequency and the frequency of skipping cycles are calculated in terms of the signal-to-noise ratio (SNR). An expression for the phase noise spectrum of the IL-OEO is also presented. The analytical model predicts the phase noise of the IL-OEO at very low offset frequencies with the accuracy rate of 75 %, in the presence of AWGN. Experimental verifications are carried out to prove the validity of the proposed analytical model.