以光子晶體陣列調整雷射模態

Abstract

本論文在一般邊射型雷射的脊狀波導上製作光子晶體陣列，利用光子晶體對光的繞射效應，引發Vernier Effect達到雷射橫向模態拍頻，使原本多模態雷射轉變為單模雷射。我們參考了耦合式共振腔雷射的方式，達到Vernier Effect以改善雷射模態。在論文中我們會先介紹Vernier Effect以及如何在邊射型雷射上產生Vernier Effect，接著我們首先使用半高寬較寬的量子點元件製作較長共振腔的元件，配合經過Vernier Effect後共振腔縱模模態的計算，證實製作光子晶體後的雷射頻譜與計算的縱模模態趨勢吻合，接著我們利用雷射頻譜半高寬較窄的量子井元件製作短共振腔的光子晶體雷射，也確實看到了單模操作的雷射頻譜。相較於其他改善雷射模態的方法，本論文證實了利用小範圍的光子晶體陣列引發Vernier Effect即可改善雷射模態，並且理論上對於不同波長的元件，我們只要調整光子晶體週期結構，即可達到模態改善的效果。在我們的實驗中，最後成功得到穩定在單模操作的雷射，最好的邊模抑制比以及半高寬分別為40dB以及0.11nm。

In this thesis, we demonstrate a laser mode modulation by photonic crystal in-plane diffraction inducing Vernier Effect. A multimode edge emitting laser has been transfer to a single mode operation laser. We refer a couple cavity laser[8] that how to induce the Vernier Effect on edge emitting laser, and enhance laser spectrum. At first, we introduce Vernier Effect and describe how we create it on our device. We use a quantum dots(QDs) sample to fabricate long cavity laser device, and it has more boarder FHWM in laser spectrum. By calculating the cavity response after Vernier Effect and comparing to our device laser spectrum with PHCs Array. And then, we show a single mode operation laser with quantum well(QW)active layer. By using QW active layer we can get much shorter cavity length and more narrow FWHM in laser spectrum than QDs laser. Comparing to other way to modulate laser mode , we demonstrate a novel way to modulate laser mode. In our work, we get a single mode operation laser with SMSR 40dB and FWHM 0.11nm.