雷射線寬是評斷雷射優劣的重要指標之一，在如光通訊、LiDAR、光原子鐘 等不同領域中扮演著舉足輕重的腳色，隨著技術的進步，對雷射線寬的要求也愈 加嚴苛。本論文提出了一種利用自注入鎖模技術降低雷射線寬的方法。該方法將 微環形共振腔作為雷射的外部腔體，透過 Rayleigh 背向散射的能量回授來實現 鎖模，進一步減少雷射線寬。與市售的外部腔體雷射相比，此技術更具經濟性， 且與互補式金屬氧化物半導體（CMOS）製程技術高度兼容，具備高集成密度的 優勢。 在本論文中也會介紹微環形共振腔的製程流程。為了驗證自注入鎖模技術對 雷射線寬的影響，因此在論文中將詳細探討線寬量測技術，根據不同的雷射線寬， 需選擇適當長度的延遲光纖，並在量測時調整極化至頻譜呈現勞倫茲曲線。此外， 研究發現，調整耦光光纖與雷射之間的距離以改變功率，會使線寬頻譜隨功率的 降低而出現拓寬的現象，但耦光光纖後的功率變化對線寬影響不大。論文還比較 了不同結構及波導材質對耦合的影響，最終選定波導高度為 100 nm 的低限制波 導作為外部共振腔的設計。最後，論文將展示如何通過不同方法實現自注入鎖模， 成功將雷射線寬壓縮至原來的五分之一。 ;Laser linewidth is one of the key indicators of laser performance, playing a crucial role in various fields such as optical communication, LiDAR, and optical atomic clocks. As technology advances, the requirements for laser linewidth have become increasingly stringent. This thesis proposes a method to reduce laser linewidth using self-injection locking technology. The method employs a microring resonator as the external cavity of the laser, achieving mode-locking through energy feedback from Rayleigh backscattering, further narrowing the laser linewidth. Compared to commercially available external cavity lasers, this technique is more cost-effective and highly compatible with complementary metal-oxide-semiconductor (CMOS) fabrication technology, offering high integration density. The thesis also introduces the fabrication process of the microring resonator. To verify the impact of self-injection locking on laser linewidth, the thesis explores linewidth measurement techniques in detail. Depending on the laser linewidth, it is necessary to choose an appropriate length of delay fiber and adjust polarization during measurement to achieve a Lorentzian profile in the spectrum. Additionally, the study found that adjusting the distance between the coupling fiber and the laser to change the power causes the linewidth spectrum to broaden as the power decreases, although changes in power after the coupling fiber have little effect on the linewidth. The thesis also compares the effects of different structures and waveguide materials on coupling, ultimately selecting a low-confinement waveguide with a height of 100 nm as the design for the external resonator. Finally, the thesis demonstrates how self-injection locking can be achieved through various methods, successfully compressing the laser linewidth to one-fifth of its original value.
