垂直共振腔面射型雷射之設計與優化

Abstract

以氮化鎵為基底的垂直共振腔面射型雷射因為諸多的優點例如: 低閾值電流、圓形光場等等，使之成為非常受矚目的光源。但是，受到製程中磊晶成長的限制，要達到較低的閾值電流仍是相當困難。另外，光增益的峰值與雷射共振腔的共振波長若彼此無法在頻域區間中對準，會降低垂直共振腔雷射的出光特性。本篇論文中使用光電數值模型以分析雷射元件之光電特性，針對低閾值電流及提升雷射光電特性的設計方法會在本文中討論。此外，共振腔特性和模態增益隨著溫度的變化也會利用數值模擬的方法於本文中討論。最後，將熱效應對雷射特性的影響考慮進設計準則中，提出針對不同元件、環境溫度的優化方法。

Gallium nitride (GaN)-based vertical-cavity surface-emitting laser diodes(VCSELs) become an attractive light source due to numerous advantages, which include low threshold current, circular beam profile, etc.. However, the low threshold current is hard to achieve because a quality epitaxial growth is still crucial. In addition, the misalignment between the gain peak and resonance wavelength would deteriorate the performance of VCSELs. The electro-optical numerical model is used to analyze the properties of device. The design rules to achieve a low threshold current and to enhance the performance of VCSELs are discussed. Moreover, the modal gain and the cavity properties are simulated with varying temperature. The designed principle which considers the thermal effect into the simulation model is presented. The relationships between temperature and both the gain characteristics and cavity properties are proposed.