Investigation On The Time Delay Signature And Bandwidth Of Chaotic Output Of Distributed Feedback Semiconductor Laser

In chaotic secure communication,Time delay signature(TDS)will reveal important information,the bandwidth(BW)of chaotic carrier signal will restrict the transmission rate of information signal,Therefore,in order to enhance the security and transmission ability of chaotic secure communication,this thesis presents two new schemes used to suppress the TDS and investigate the BW of chaotic laser from distributed feedback semiconductor laser,they are the semiconductor laser system with external double optical injection and phase modulation optical feedback by self chaos light and the semiconductor laser with external unidirectional double optical injection and phase modulation optical feedback.The simulation results showed that: within the selected parameter ranges,the value of TDS of chaotic laser output in most regions of these two schemes are far less than 0.2,that is,eliminate the auto correlation performance of chaotic laser output.Then the BW of the chaotic light output corresponding to these two schemes are investigated under the parameters conditions of effectively suppressing TDS,the results show that:for the first scheme,the BW decreases with increasing master lasers’ s feedback coefficient;the BW increases with increasing injection coefficient and slave lasers’ s feedback coefficient,the BW first increases with the increase of the pumping factor,then tends to be flat and slightly decreases.For the second scheme,the BW increases firstly and then decreases with the increase of the feedback coefficient of the main laser,the BW increases with increasing injection coefficient and slave lasers’ s feedback coefficient,The BW first increases and then tends to be flat with the increase of the pump factor of the master laser.The BW increases rapidly and then decreases slowly with the increase of the pump factor of the slave laser.The BW increases gradually and then decreases with the increase of frequency detuning.The maximum 3d B BW of chaotic laser obtained is 17 GHz and 20 GHz,respectively,by using these two schemes under the conditions of effectively suppressing the TDS,Finally,the output chaotic light with high BW and low TDS generated in this paper is used as the physical entropy source,the simulation generates physical random numbers,And the physical random number passed the performance index test.