Static and dynamic effects of lateral carrier diffusion in semiconductor lasers

Jianzhong Li, Samson H. Cheung, Cun-Zheng Ning

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Electron and hole diffusions in the plane of semiconductor quantum wells play an important part in the static and dynamic operations of semiconductor lasers. It is well known that the value of diffusion coefficients affects the threshold pumping current of a semiconductor laser. At the same time, the strength of carrier diffusion process is expected to affect the modulation bandwidth of an AC-modulated laser. It is important not only to investigate the combined DC and AC effects due to carrier diffusion, but also to separate the AC effects from that of the combined effects in order to provide design insights for high speed modulation. In this presentation, we apply a hydrodynamic model developed by the present authors recently from the semiconductor Bloch equations. The model allows microscopic calculation of the lateral carrier diffusion coefficient, which is a nonlinear function of the carrier density and plasma temperature. We first studied combined AC and DC effects of lateral carrier diffusion by studying the bandwidth dependence on diffusion coefficient at a given DC current under small signal modulation. The results show an increase of modulation bandwidth with decrease in the diffusion coefficient. We simultaneously studied the effects of nonlinearity in the diffusion coefficient. To clearly identify how much of the bandwidth increase is a result of decrease in the threshold pumping current for smaller diffusion coefficient, thus an effective increase of DC pumping, we study the bandwidth dependence on diffusion coefficient at a given relative pumping. A detailed comparison of the two cases will be presented.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsR.H. Binder, P. Blood, M. Osinski, Y. Arakawa
Number of pages9
StatePublished - 2002
Externally publishedYes
EventPhysics and Simulation of Optoelectronic Devices X - San Jose, CA, United States
Duration: Jan 21 2002Jan 25 2002


OtherPhysics and Simulation of Optoelectronic Devices X
Country/TerritoryUnited States
CitySan Jose, CA


  • Carrier diffusion
  • Current modulation
  • Nonlinearity
  • Semiconductor laser

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics


Dive into the research topics of 'Static and dynamic effects of lateral carrier diffusion in semiconductor lasers'. Together they form a unique fingerprint.

Cite this