Comparison of linewidth enhancement factor between p-doped and undoped quantum-dot lasers
- Resource Type
- Periodical
- Authors
- Jungho Kim; Hui Su; Minin, S.; Shun Lien Chuang
- Source
- IEEE Photonics Technology Letters IEEE Photon. Technol. Lett. Photonics Technology Letters, IEEE. 18(9):1022-1024 May, 2006
- Subject
- Engineered Materials, Dielectrics and Plasmas
Photonics and Electrooptics
Quantum dot lasers
Laser theory
Laser modes
Optical refraction
Optical variables control
Refractive index
Quantum dots
Quantum well lasers
Optical pulses
Pulse measurements
Linewidth enhancement factor (LEF)
quantum dot (QD)
semiconductor lasers
- Language
- ISSN
- 1041-1135
1941-0174
The optical linewidth enhancement factor (LEF) of a p-doped quantum-dot (QD) laser is measured below threshold and compared with a theoretical calculation. The optical gain, refractive index, and LEF are well matched with our theoretical model when the thermal effect is isolated by an additional pulse current measurement of the LEF. We also theoretically calculate the LEF of an undoped QD Fabry-Pe/spl acute/rot (FP) laser assuming that the structure of the undoped FP QD laser is the same as that of the p-doped QD FP laser except the p-type doping. The changes in modal gain and refractive index due to the respective QD ground and excited states are calculated. Based on the theoretical results, we show that the LEF of the p-doped QD laser is smaller than that of the undoped QD laser due to the reduced transparency carrier density.