Nonlinear Analysis Of High Power Chaotic Fiber Laser Output

Chaotic laser with the characteristics of the noise-like,good randomness and unpredictability is widely used in chaotic secure communication,fast random number generator,optical fiber fault detection and optical fiber sensing,etc.In general,the chaotic laser output of the oscillators is relatively small and requires power amplification to achieve a higher power for further development and application.As a laser with special structure,the resonant cavity and gain medium of the fiber laser can be located in the waveguide cavity,so it has the advantages of high conversion efficiency,good stability and simple structure.It has been developed rapidly in recent decades.With the development of nonlinear chaotic dynamic,there are higher requirements for the characteristics of chaotic sequences.For the chaotic fiber laser,the complexity of chaotic system is determined by its own nonlinearity,instability and uncertainty.Complexity is a quantitative description of the complexity of a system.In practical applications,a greater complexity of the chaotic sequence means the stronger randomness,the higher security of the secure communication,the higher accuracy of the chaotic ranging.Therefore,it is very important to obtain a chaotic laser with high power and high complexity by using an effective method.In order to realize the high power output of chaotic fiber laser with high complexity,and extended the application.In this paper,the chaotic characteristics of Er³⁺-doped fiber lasers and Yb³⁺-doped fiber lasers during amplification are studied,and the complexity of chaotic sequences under different conditions is analyzed.The research work is mainly summarized as follows:1.This chapter briefly introduces the characteristics,classification,development and application prospect of fiber lasers,expounds the development process and prospect of optical chaos.2.Detailed analysis of several common fiber laser chaotic method and principle,and introduces the complex chaotic sequence characterization and permutation entropy algorithm.3.The chaotic laser generated by the erbium-doped fiber ring laser is amplified and the output characteristics of the laser are studied experimentally.By controlling the polarization state of the fiber laser cavity and the driving current of the amplifier,different chaotic states are obtained and the complexity of the chaos was carried out by permutation entropy function.It is found that the range of higher permutation entropy can be obtained by adjusting the state of the polarization controller and the power amplification condition,and an optimized chaotic laser with higher permutation entropy is obtained.4.The experiments on the dynamic characteristics of ytterbium-doped chaotic fiber laser system in the process of two-stage amplification are carried out.The complexity of chaotic sequences under different conditions is analyzed.The output power of 1.7W is achieved with the wavelength of 1069 nm.Compared with the main amplifier,the preamplifier have higher PE due to the preamplifier used the single mode ytterbium-doped fiber.The system can obtain high power chaotic laser output with higher complexity.The experimental results have certain reference value for obtaining a high power chaotic laser with high complexity.