Study On The Technology Of Weak Optical Signal Enhancement Via Stochastic Resonance

With the advancement of science and technology, the conventional detectionmethods of weak signals can not meet the requirements for exploring themacroscopic world and microscopic world. It is in urgent of developing new signalprocessing techniques in many applications field, such as laser radar, optical spacecommunication and optical remote sensing. Therefore, the study of the nonlinearoptical amplification technology which can obtain a high signal-to-noise ratioenhancement has important scientific and practical value. In recent years, thecomplexity of noise has been known through the study of stochastic resonance. Insome nonlinear systems, noise has its positive side. That is a weak periodic signalcan be optimized by the presence of an appropriate level of noise. The uniqueadvantages of stochastic resonance in signal processing led to widespread concern.Especially, stochastic resonance has a great prospect in optical informationprocessing, when it is combined with the nonlinear optical technology. In order toextract weak light signals in a strong noisy background, the method of nonlinearstochastic resonance theory has been studied. The main results of this paper aresummarized as follows:1．Research background and significance of the technologies of weak lightsignal enhancement were analyzed comprehensively. Key issues of weak-light signaldetection were discussed thoroughly. A brief introduction of the methods to detectweak light signals and the theory of stochastic resonance are given.2．The typical bistable stochastic resonance theory, including the theoreticalmodel and system parameter optimization is researched. Based on the theoreticalmodel, a weak signal under a noisy background was enhanced. The relationshipbetween the noise intensity and the nonlinear system is also investigated via outputsignal-to-noise ratio.3．An optical bistability theoretical model was deduced in photorefractive unidirectional optical ring cavity. It is found that the output properties of the systemare mainly determined by the system parameters, such as the crystal length, theapplied electric field and so on.4．An all-optical stochastic resonance theory was proposed based on the abovestudies. The influences of the external noise and bistable system parameters onstochastic resonance are also numerically analyzed in the optical bistability system.The conclusions of the mathematical analysis reveal that the system can show a goodperformance in weak optical signal processing, regardless of whether the input signalis periodic or aperiodic...