A Research Of Secure Chaos Communication Based On Phase Encrypted Feedback Laser

Semiconductor laser(SL)supports the encryption and decryption of information on physical layer,it is easy to realize high dimensional chaotic output under certain conditions,and it's widely used in chaotic secure optical communication,high speed random number,chaotic key distribution and other fields.With the deepening of the research,it is found that the chaotic laser light source will expose the security defects,such as using the delay analysis technologies to obtain the SL external structure information,which will increase the possibility of the attackers using the delay information to try to reconstruct the laser chaos system,which will restrict the application of SL.The encryption of SL or the introduction of nonlinear factors can effectively ensure the security of the output chaos of the laser system.Based on the external cavity feedback semiconductor laser,the phase modulator is introduced into the feedback external cavity,and the digital random signal or analog signal is loaded in the phase modulator,which can not only be used as the phase encryption scheme to encrypt the operation,but also introduce the non-linear factor to optimize the chaotic output of the feedback.Based on the random phase modulation feedback laser,the structure of phase dual-feedback and the cascaded phase modulation structure are proposed,and the effect of phase modulation parameters on time delay signature(TDS)and phase modulation rate is studied emphatically.The results show that the random phase modulated dual-feedback laser can successfully conceal TDS at high speed phase modulation rate,but it cannot eliminate the phase modulation rate in the spectrum.When controlling high speed phase modulation rate of 15Gbit/s~28Gbit/s and low speed phase modulation rate lower than 8Gbit/s,the cascaded random phase modulated lasers not only can successfully conceal the TDS,but also can eliminate the information of low speed phase modulation rate on spectrum.Based on sinusoidal signal phase modulated feedback lasers,the effect of phase modulation rate on the enhancement of chaotic bandwidth is studied,and the maximum bandwidth is up to 30.9GHz.This paper studies the communication performance of the three structured phase modulated lasers,and analyzes the illegal attack methods: injection-locking method,direct linear filtering(DLF)method,key losses,delay information losses and the phase modulator parameter mismatch,to analysis of system security.At the appropriate rate of information transmission,it can not only guarantee the legal demodulation performance of the information,but also successfully resist several illegal attacks,so as to ensure the security of the system.The feedback mirror of phase conjugate feedback(PCF)laser adopts phase conjugate mirror(PCM),which introduces nonlinear factors to laser,which is more complex than conventional optical feedback(COF)lasers,and the synchronization of PCF lasers is very few.Based on PCF lasers,the synchronization conditions of closed-loop structures are presented: at the receiving end,appropriate phase shift are introduced into the feedback items or injected items,corresponding to 1.13?,0.44?(1.44?)respectively when the frequency detuning is zero.The synchronization performance of the two closed-loop structures has little difference,and it is easier to realize synchronization than COF lasers.Because PCF lasers have about 20% larger effective bandwidth than COF laser chaotic output,the communication performance of the two synchronous structures of PCF lasers is better than that of COF lasers communication system.