光達(Lidar)這項技術一直以來被運用在許多科技產品上，像是機載光達藉由光達得知飛機與地面的距離，測量大範圍的地形起伏或是森林面積；在掃地機器人方面，也利用了雷射光達計算與物體的距離避免機器人撞到和控制轉彎；而在近期，自駕車的概念逐漸萌起，越來越多公司開始研究如何發展低成本、誤差低的光達系統。而在眾多光達系統中，又因價格低、功率符合安全規範且偵測距離遠的調頻連續波光達(FMCW Lidar)佔有較大的優勢，關於其相關研究也隨之而來。在早期的研究中，為了產生線性啁啾之訊號，常使用直接調制的方式來改變雷射的輸出頻率，然而因其線性程度不理想，在測距上造成嚴重的誤差，往往需要額外的儀器來修正，使得光達系統太過複雜。近期的研究中則是使用了可調式雷射來產生啁啾訊號，但其成本過高難以實現於自駕車上。此篇論文展示了光注入系統，利用週期一的動態特性配合外部調制的方式，產生線性啁啾光訊號，並且藉由第N階的調制邊帶，達到N倍頻的效果，進而提升光達的分析能力。

Lidar has become more and more important recently. In FMCW lidar, how to generate linear chirped signal is an important issue. Besides, to improve range resolution, a chirped signal with large bandwidth is required. In this paper, four times chirped bandwidth is achieved using optical injection system and external modulation. The error of range testing is around 1~2%, witch shows great accuracy and stability in this system.

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