摘要：在介紹非線性科學和混沌的基礎上，基於DFB半導體激光器原理，建立理論模型並實驗研究證實外部光注入DFB激光器將輸出衆多的非線性動力學行爲特徵，理論模型和試驗結果在外部光注入和頻率失諧條件下具有良好的偶合效果。本文給出了其輸出特性隨注入光強度和頻率失諧量變化的1系列動力學特徵圖。實驗結果表明：激光器的動力學行爲對外部的微擾10分敏感；在不同外部光注入或頻率失諧條件下，激光器可以呈現出多種非線性動力學特徵。文章最後給出了外部光注入下DFB激光器非線性動力學狀態分佈圖；當激光器處於複雜動力學區域時，其頻譜爲連續譜；在連續譜上存在多個明顯的峯，其對應的頻率定義爲特徵頻率，特徵頻率的大小與注入光的強弱以及頻率無關。
關鍵詞：非線性動力學；混沌；DFB半導體激光器；外部光注入；失諧頻率
The nonlinear dynamics of a distributed feedback semiconductor laser subjected to external optical injection
Yang Qi
Physics School of Science and Technology,Southwest University,Chongqing,400715,China
Abstract: In this paper firstly introduced the nonlinear science and chaos. Then a theory model based on the principle of DFB-LD has been presented. A comparison of the observed characteristics with the predictions of a coupled rate-equation model shows quantitative agreement over a wide range of injection parameter or the detuning frequency. The nonlinear dynamic characteristics of distributed feedback (DFB) semiconductor lasers subject to external optical injection have been investigated experimentally. The output dynamical characteristics are mapped as a function of the power of optical injection and the detuning frequency. Experimental results show that DFB semiconductor laser is very sensitive to external perturbation and can exhibit various nonlinear dynamical characteristics when subjected to different external optical injection. In the end of this paper we presented the mapping of the nonlinear dynamics characteristics of DFB-LD subject to external optical injection. When the laser exhibits complex dynamic, its spectrum is continuous, and there are several peaks in the spectrum. The magnitude of the frequency that the peaks correspond to respectively has nothing with the power and the frequency of injection field.
Key words: nonlinear dynamics; chaos; DFB-LD; external optical injection; detuning frequency
1、緒論
1.1 引言
2O世紀6O-7O年代建立的`非線性科學是自然科學的重大發展。1些物理學家認爲非線性科學是2O世紀物理學繼相對論、量子力學之後的第3次科學革命。非線性科學的誕生標誌着人類對自然界的認識由線性進入非線性領域，揭示了自然界存在着更普遍的、既確定又隨機的混沌現象及其特有的非線性規律[1]。
什麼是非線性科學呢?線性表示量與量之間成正比關係，其部分之和等於整體，描述線性系統的方程遵從疊加原理；非線性指整體不等於部分之和，疊加原理失效[3]。數學上,主要通過對算子的分析來討論線性和非線性。如果1個算子L滿足: