本研究是以半導體雷射之光注入系統為基礎，發展寬頻渾沌訊號產生器。
渾沌訊號擁有較寬且平坦的功率頻譜，在分析渾沌訊號時，頻寬為其中一個描
述訊號特性之工具。目前常見的頻寬計算方法可分為下述兩種: (1)從直流到佔
有80 % 總功率的頻率範圍，(2)中間佔有80 % 總功率的頻率範圍。使用上述兩
種頻寬計算方法有時會使窄頻之週期震盪訊號被誤算為寬頻訊號，因此，本研
究前半部提出一頻帶計算方法去計算訊號之有效頻寬，有效頻寬之定義為佔有
前80 % 總功率之各段頻帶寬度總和。在此我們利用這三種計算方法比較由光注入
系統所產生之訊號的頻寬，並比較自相關峰值半高全寬和各定義頻寬值之關係。
經由模擬結果發現，有效頻帶計算方法可清楚的分辨窄頻週期訊號和寬頻渾沌訊
號，並且有效頻帶計算之頻寬值和Peak to sidelobe level (PSL) 呈現反比之現象。因
此，有效頻帶計算方法為較好的頻寬量測方法。
經由上述成功的利用有效頻帶計算方法來描述訊號之特性，接著我們利用有效
頻帶計算方法探討本研究後半部之主題: 環狀排列混沌訊號產生器，目的為產生更
寬頻之混沌訊號。環狀結構為利用多顆雷射串聯注入並讓末顆雷射打回首顆雷射
之架構。因此，環狀結構可視為光注入系統，我們討論討論下列兩部分: (1)注入強
度對於雷射頻寬之影響，(2)雷射的頻率差對於雷射之影響。其模擬結果如下:
1. 環狀排列之雷射頻寬會隨著注入強度增強而增加。在相同注入強度之範圍
下，環狀結構所能產生之混沌訊號最大頻寬是一般光注入系統的2 倍。
2. 環狀結構雷射之頻寬在改變兩雷射的頻率差時，必須同時考慮兩雷射的鬆弛
震盪頻率和注入渾沌訊號之響應頻率。因此，環狀結構之頻寬並不會隨著兩
雷射的頻率差增加而增加。經由適當的調整兩雷射頻率差，比較環狀結構和
光注入系統的最大頻寬，環狀結構是光注入系統的1.8 倍。

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