Optical Gain and Lasing Properties of InP/AlGaInP Quantum-Dot Laser Diode Emitting at 660 nm

• Published in: IEEE journal of quantum electronics 2019-04, Vol.55 (2), p.1-7
• Main Authors: Zhihua Huang, Zimmer, Michael, Hepp, Stefan, Jetter, Michael, Michler, Peter
• Format: Article
• Language: English
• Subjects: Absorption spectra; AlGaInP; Amplification; Current density; Emission analysis; Energy states; Indium phosphides; InP; Laser excitation; Lasers; Lasing; Measurement by laser beam; optical gain; Optical properties; Optical variables measurement; quantum dot; Quantum dot lasers; Quantum dots; Quantum efficiency; red-emitting laser diodes; Self-assembly; Semiconductor lasers; Spontaneous emission; Stimulated emission; Temperature measurement; Threshold currents
• ISSN: 0018-9197; 1558-1713
• DOI: 10.1109/JQE.2019.2896643

We investigated the optical gain properties and lasing characteristics of a pulsed electrically pumped laser structure, which consists of a single layer of self-assembled InP quantum dots (QDs) assembled in (Al 0.10 Ga 0.90 ) 0.52 In 0.48 P barriers. The optical gain and absorption spectra were obtained by analyzing the amplified spontaneous emission as a function of the excitation length. At a current density of 1.2 kA/cm 2 , an internal optical loss value of 5 ± 2 cm -1 and a peak modal gain of 39.3 cm -1 corresponding to a material gain of approximately 2675 cm -1 per QD layer were determined at room temperature. For a 2.24-mm-long laser with uncoated facets emitting at 660 nm, a low threshold current density of 281 A/cm 2 and an external differential quantum efficiency of 34.2% were determined. The internal quantum efficiency of 66% and the transparent current density of 65.8 A/cm 2 for a single layer of QDs were also demonstrated.