Investigation On Chaotic Signal Generation With Low Time-delay Signature Based On A Semiconductor Laser Subject To Double Filtered Optical Feedback

Output chaotic signals from semiconductor lasers which based on external disturbance have attracted more and more attention because of its great application value in chaotic secure communication,high speed random access and the chaotic radar,etc.In many ways of chaotic laser generation,optical feedback semiconductor laser is very popular because of simple structure,easy operation,easy to obtain high dimensional chaotic laser.However,optical feedback semiconductor laser output chaotic signal has the time-delay signature,and it hindered the optical feedback semiconductor laser application in related fields,reduce the security of secret communication,reduce the statistical properties of a random number and reduce the chaotic radar measurement precision accuracy.So,investigation on light feedback semiconductor laser chaos suppression chaos output suppression theory and technology has important practical significance.Generally,it's mostly plane mirror in the external cavity of optical feedback semiconductor laser.Studies have shown that using the method such as F-P interferometer or the dispersion characteristics of optical fiber Bragg grating filter to replace the plane mirror,can better suppress the effect of the system output delay characteristics.Based on this,using the method of two F-P interferometer to replace the plane mirror in double plane mirror of optical feedback semiconductor laser,and construct a double filter feedback semiconductor laser system in this paper.And theoretical analysis of the feedback strength,feedback time,filter bandwidth,and frequency detuning between the central frequency of the filter and the solitary laser on the system output the influence of time delay characteristics of chaotic signal.The results showed that: if the feedback time was roughly half of the semiconductor laser relaxation oscillation period of time in the double filter feedback system which can get ideal effect.For 2? was 2.92 ns or 3.08 ns,if the feedback intensity is appropriate,Can further suppress the time-delay signature.In addition,by analyzing frequency detuning between the central frequency of the filter and the solitary laser and filter bandwidth effects on time-delay signature suppression.In order to determine the parameter space of filter bandwidth where chaotic signal with low time-delay signature,the map of timedelay signature evolution in the parameter space of frequency detuning and filter bandwidth have been drew.