850nm面射型雷射之近場光學研究

Abstract

本論文主要在探討GaAs垂直共振腔面射型雷射近場光學，與一些雷射隨溫度改變的特性，用於研究的雷射有三種不同的結構：一為氫離子佈植型電流侷限結構，第二種為矽離子佈植型電流侷限結構，另一種為氧化型電流侷限結構。 由近場光學的結果來分析，氧化型電流侷限結構有最好的電性與光學特性，而氫離子佈植型電流侷限結構的電性與光學特性最差。在研究雷射近場時發現氧化型電流侷限結構在臨界電流以下時，可以量測到較高階的Hermite-Gaussian 與Laguerre-Gaussian兩種模，並且有兩組不同大小Hermite-Gaussian模，較大那組Hermite-Gaussian的波長較長，是因為電流造成光侷限的效應，最後雷射發光的主要橫模，較小那組Hermite-Gaussian的波長較短，為氧化層氧化形成光侷限的效應。

In this thesis, We have investigated the near-field patterns of 850nm vertical cavity surface emitting lasers (VCSELs) to discuss the impacts of the structural parameters on the devices. The temperature dependent characteristics of the VCSELs have been investigated as well. We have analyzed three types of laser structures: proton-implant, silicon-implant, and oxide-confined VCSELs. In three laser structures, oxide-confined VCSEL shows the best current and optical confinement. Proton-implanted VCSEL is the worst one. Interestingly, when the oxide-confined VCSEL operates at subthreshould, both the high order Hermite-Gaussian and Laguerre-Gaussian modes can be clearly observed. One set of Hermite-Gaussian modes with a longer emission wavelength and a larger mode size are considered to be supported by a carrier-induced aperture. Another set of Hermite-Gaussian modes with a shorter emission wavelength and a smaller mode size are considered to be supported by the built-in oxidized aperture and it will not be the dominant mode above the threshold condition.