Research On Chaotic Characteristics Of Low-frequency Electrical Noise In Semiconductor Laser Diodes

In the 1960s, semiconductor laser diodes were devised, with the development of optoelectronic technology. Semiconductor lasers are widely applied in the domains of high-technology such as industry, medicine treatment, military science and information technology etc.,It is a kind of key implement in the information technique domain.The factors affecting the reliability are one of the primary sources producing low-frequency electrical noise, which intensity can reflect the quality and reliability of devices.Conventional methods for analyzing the noise based on the power spectrum in the frequency domain focus only on the whole singularity of noise signal but nelect the interior relation of time frequency.In this paper,it is researched how to use the Chaos,Fractal and other nonlinear theories on the reliability of semiconductor lasers.The work in this thesis is supported by the National Natural Science Foundation of China (Grant No.60471009)"Research on detection method of noise in high-power semiconductor laser diodes and their reliability correlation"and the high technology key project of Jilin province (Grant No. 20040301-4)"The quality detection and screening equipment exploitation of high-power semiconductor laser diodes". This work is carried out mostly in detection technology of low-frequency electrical noise in LDs.Firstly, the production and development of semiconductor lasers is reviewed, and their application in industry, medicine treatment, military science and information technology and so on is introduced. The representation of low-frequency electrical noise used in reliability of LDs is described. And then, the application of Chaos theory in signal is discussed. And we propose the Chaos theory is applied in the noise reliability.Secondly, to have more detailed understanding of the noise characteristics of semiconductor lasers, the thesis introduces the components of low-frequency noise of semiconductor laser, based on the statistical properties of noise. It includes the white noise, G-R noise and 1/f noise. The sources of white noise and G-R noise are illustrated.Thirdly, the fundamental theories of 1/f process and wavelet transformation are introduced; the correlation and variance characteristics of binary wavelet coefficient are deduced; the methods to synthesize 1/f fractal signal are investigated, especially, the computer simulation experiments of synthesized 1/f fractal signal based on wavelet reverse transformation are carried out in detail, and other methods are also introduced; concentrating on the problems of the parameters and wave estimation for 1/f fractal signal in additive white noise background, we carry out experiment research, and the maximal likehood estimation is introduced. The simulation of 1/f noise is used by Labview.Forth, after nonlinear characters of low-frequency noise are confirmed, the LF noise is researched by two nonlinear methods of Chaos and Fractal. By Cao method, the accurate phase reconstruction parameters of noise are obtained. Through the simulation experiment and real-life data analysis, it is found that the calculation of correlation dimension and largest lyapunov exponent is influenced by white noise.Finally, the essence of semiconductor lasers noise is analyzed by Chaos and Fractal. And the model of noise is discussed. After pick-up the nonlinear dynamics parameter, we explore the mechanism of noise combined with the Fractal physics. Based on the experiment and simulation, the chaos model of semiconductor lasers'noise is proposed.