Study On Chaotic Characteristics Of Light-injected Erbium-doped Fiber Laser

The chaotic fiber laser has the characteristics of wide bandwidth,strong anti-interference ability,and high randomness.It has a wide range of applications in the fields of chaotic fiber sensing,chaotic lidar,and chaotic secure communication.In recent years,optical fiber sensing based on chaotic sources has attracted more and more attention.The chaotic source can realize long-distance optical time-domain reflection,temperature sensing based on Brillouin scattering and distributed pressure sensing.And pressure,temperature,and concentration sensing were realized by chaotic fiber laser source using ring-down technology.The stability of the chaotic source and the complexity of the chaotic signal restrict the accuracy of chaotic sensing.The short-term and long-term stability of the chaotic system and the chaotic output complexity were analyzed in this work on the basis of ensuring the chaotic complexity through chaotic light injection.The output characteristics of chaotic fiber laser under optical injection are studied experimentally.Chaotic fiber laser with ring cavity is generated based on the nonlinear Kerr effect of fiber.The chaotic laser generated by the master laser is injected into the chaotic erbium-doped fiber laser through an optical isolator and a fiber coupler to achieve external light injection.The time series,spectrum,autocorrelation,stability and complexity of chaotic signal from the injected slave laser are studied by injecting different power of chaotic signals from the master laser.In this work,based on the optical injection technology,we conducted an experimental study on the chaotic erbium-doped fiber laser,and analyzes the complexity and stability changes before and after injection.The main work is as follows:1.The development progress and application fields of erbium-doped chaotic fiber lasers was introduced.The development of light injection technology in the field of lasers was summarized.The research background and significance of this article were showed.2.The theoretical basis of the chaotic signal generated by the fiber laser-the Kerr modelwas expounded in detail,and the basic characteristics of the chaotic signal and the chaotic evaluation method were summarized,including the analysis method of the chaotic complexity,the source of instability and the evaluation method.3.The light injection single-wavelength chaotic erbium-doped laser is experimentally studied,and the permutation entropy,stability and dynamics of the chaotic signal before and after injection are analyzed.The experimental results show that the wavelength detuning of the master and slave lasers is in the range of-0.3nm to 0.3nm,the injection power ratio is in the range of 0.03 to 0.16,the permutation entropy of the chaotic signal is stable above 0.99,and the permutation entropy standard deviation is less than 0.0012;indicating that the injected chaotic signal has a higher complexity while achieving higher stability,and restraining the time jitter caused by short-term instability.4.The optical injection multi-wavelength chaotic erbium-doped laser has been experimentally studied,and the permutation entropy and stability of the output state of the fiber laser before and after injection have been analyzed.The experimental results of light injection into the multi-wavelength chaotic erbium-doped laser show that the multi-wavelength chaotic signal has higher complexity due to the larger peak-to-peak value,but the degree of stability is not enough,and there is short-term instability.After injection,the stability of the chaotic signal is enhanced,and high complexity is obtained,which overcomes the short-term unstable chaotic signal.5.The self-pulse of erbium-doped fiber laser is analyzed,and the suppression of self-pulse by chaotic light injection is studied.The experimental results show that the self-pulsation is caused by the rapid return of erbium ions from the excited state to the ground state due to aggregation.The chaotic self-pulsation can be suppressed by resonant light injection,and higher complexity is obtained.Therefore,chaotic light injection can stabilize the chaotic output of the laser and suppress long-term instability.