Theoretical Research On Synchronization And Communication Between Chaotic Semiconductor Lasers With Injection Locking And Feedback

Owning to have wide bandwidth,strong anti-interception ability,fast transmission rate and low attenuation,the optical chaotic signal has become an excellent option for secure communication.And recently the secure communication based on optical chaos has risen rise scholars'attention and achieved fruitful research results.Synchronization is the basis of chaotic communication,so it is required that the transmitter and receiver must be identical synchronized.The receiver can recover the transimission information by monitoring the synchronization error in the fiber llink in real time and comparing it with the local signal.Although there are many ways to make the laser enter to chaos,such as:all-optical feedback,optical injection and electro-optical feedback,etc.,the optical injection can make the dynamic characteristics and the output signal of the laser more complicated,the frequency spectrum is more flat,and at the same time,it has better performance in maintaining synchronization quality when there is internal noise and parameter mismatch of the laser.Although the chaotic signal is used as carrier signal can achieve high security,for optical communication systems,once the time delay is determined,then techniques such as artificial neural networks can be used to reconstruct the potential chaotic dynamics,so it is very important that the system has concealed time-delay signature(TDS).By studying the latest research results at home and abroad,this paper proposes two chaotic optical communication schemes based on previous studies,which can achieve high security,bandwidth,speed and quality communication.The main research results are as follows:(1)The wavelength division multiplexing(WDM)-based bidirectional chaotic communication for semiconductor lasers system with time delay concealment is studied.In the scheme,the output of a master semiconductor laser(MSL)is injected into slave semiconductor lasers(SSLs)with optical feedback and electro-optical phase feedback to drive SSLs to achieve chaotic synchronization.By calculating the largest Lyapunov exponent(LLE),Lempel–Ziv complexity(LZC)and permutation entropy(PE),we find that the system can generate the chaotic signal with high complexity.We also demonstrate that the chaotic signal bandwidth obtained is as high as 24.68GHz by selecting the suitable parameters;this configuration intrinsically conceals the electro-optical phase feedback time delay signature(TDS)and optical feedback TDS in transmitted variable;this delayed chaotic dynamic is identically synchronized when the parameters of emitter are exactly matched with that of receiver;while the external and internal parameters'mismatch between emitter and receiver can lead to the decrease of the synchronization quality.In addition,the result reveals that the channel spacing has influence on cross-correlation coefficient(XCF)quantifying synchronization quality.At last,the messages introduced at two ends of the link can be successfully encrypted and decrypted,realizing high-quality bidirectional communication at a high rate.(2)A bidirectional secure communication between chaotic semiconductor lasers with phase modulation optical feedback is studied.The MSL enter chaos by phase-conjugate feedback(PCF),and the output light of the MSL is injected into the SSLs by BS.At the same time,the SSLs are also subject to phase-modulated optical feedback.By selecting appropriate parameters,calculating the LZC and sorting entropy PE of the system output,it is proved that the system rises a high-dimensional chaotic signal,and the effective bandwidth of the output signal can reach20.32GHz.By calculating ACF and DMI,it is proved that all TDS information in the system is successfully hidden.In terms of synchronization performance,XCF is calculated to quantitatively analyze the effect of SSLs on synchronization performance when the parameters are completely consistent and some parameters are mismatched.Finally,the process of bidirectional communication was successfully simulated,and the Q-factors under different transmission rates when?_inj=80ns^-1 and?_inj=120ns^-1 were quantitatively analyzed,indicating that the system can achieve high-speed and high-quality communication.This paper establishes and solves the mathematical model of the chaotic semiconductor laser communication system,and the dynamic characteristics and safety of the system are comprehensively analyzed.It is proved that the two new types of chaotic systems using optical injection feedback proposed in this paper can not only generate high-complexity,high-bandwidth chaotic signals,but also effectively conceal the TDS information;comprehensively studies the synchronization of the system in the presence of noise and parameter mismatch.Finally,the bidirectional communication under the high bit transmission rate was successfully realized,and the communication quality under different transmission rates was quantitatively analyzed by calculating the Q-factor.The optical chaotic communication system proposed in this paper not only draws on the rich achievements of the predecessors,but also carries out innovation and improvement,which has a positive effect on the development of optical communication.