Study on Gain Spectrum of Semiconductor Quantum Dot Light Emitters

• Main Authors: Yeh, Ting-Yu, 葉庭聿
• Other Authors: Lin, Gray
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/50216483966833657341

碩士 === 國立交通大學 === 電子研究所 === 99 === We discuss an alternative segmented contact method for accurate optical gain and loss spectra calculations of InAs/InGaAs quantum dot (QD) active materials. The error usually comes from unguided spontaneous emission. In order to eliminate it, triple biased sections against double biased section in conventional segmented contact method scheme is applied, and the error is reduced by subtracting background signal resulting clean and accurate gain and loss spectra [1]. In this thesis, we demonstrate the characterizations of QD ridge waveguide laser diodes firstly. Then, a set of detail analysis is applied between conventional and improved segmented contact methods. The devices’ current density versus modal gain curve is measured to a precision of 95.8% compared with that extracted from typical ridge waveguide laser process. The effect caused by absorber shorted to ground or not is discussed. The internal optical mode loss is also described. Finally, we demonstrate the unamplified electro-spontaneous emission spectra from conventional and improved methods. By improved segmented contact method, characterization of a semiconductor laser device could be done on a single sample instead of processing lots of cavity lengths. On the other hand, one can characterize very low gain material samples that are difficult to extract by other techniques.