Theoretical And Experimental Study Of Chaos Generation With Optical Feedback In The He-Ne Laser

This paper gives an overview of the relevant basic concepts of chaos, and introduces the nonlinear dynamic equation and stability condition of the single mode He-Ne laser(632.8nm). The dynamic characteristics of the He-Ne laser which could generate chaos with optical feedback.Based on the external optical feedback mechanism, chaos generation of the He-Ne laser(632.8nm) is demonstrated theoretically and experimentally. The paper focuses on the dynamics of the He-Ne laser with the single feedback and double feedback.In the single feedback, under the condition of the fixed pump current and the length of the fixed external cavity, the impact of the different feedback coefficient on the dynamics of the He-Ne laser is studied theoretically and experimentally, and the two kinds of results are basically consistent. The numerical and experimental results show that the He-Ne laser can enter into chaos by the route of periodic bifurcation and output the increasing chaotic bandwidth with increasing feedback coefficient. On the other hand, under the condition of the fixed pump current and feedback coefficient, the impact of the different feedback length on the dynamics of the He-Ne laser is showed theoretically. The numerical simulation results demonstrate that the He-Ne laser can enter into chaos by the route of periodic bifurcation and output the increasing chaotic bandwidth with increasing feedback length. In addition, apart from the influence of the feedback coefficient and the feedback length on output of the He-Ne laser, the detuning function also affects the output of the laser which manifests a phase factor(gain phase factor and saturated phase factor) will affect the output of the He-Ne laser.In the double feedback, the impact of two external feedback coefficient and feedback length on the He-Ne laser is discussed theoretically. The numerical simulation results indicate that comparing the dynamics characteristics of the single feedback, the He-Ne laser in the double feedback is a complex dynamic system, which can generate chaos and higher bandwidth more easily.Because the chaotic signal has characteristics of natural confidentiality, anti-interference and unpredictability, chaos takes great average in secure communication and anti interference location. Due to the He-Ne laser has its own characteristics, such as good coherence, cheap price and short wavelength and so on, it is expected to get better application in the chaotic ranging and chaotic sensing. So the research work has potential value for optical chaotic applications.