A steady-state self-consistent computer model of twin stripe double hererostructure semiconductor lasers.

  • Tribhawan Kumar

Student thesis: Doctoral ThesisPhD


Twin stripe laser structures show great promise in integrated optics systems. It has been demonstrated in the recent years that the optical interaction from such structures produce properties such as beam steering, pulse generation and bistability. The thesis describes a computer model of the lateral behaviour of such a device. The model takes into account current spreading in the p-type confining layer, the effect of lateral diffusion of carriers in the active layer and bimolecular and stimulated radiative recombinations in a self-consistent manner. The device operating below threshold becomes a special case and can be analysed without including the stimulated recombination effect in the full model. The assumptions made in this model are such that the results show the effect of quasi-Ferri level pinning above threshold due to gain saturation. Results for the single stripe laser are presented to compare with other existing models without any extra efforts. The thesis presents results of the optical field distributions of a twin stripe laser found consistent with the carrier density and current density distributions under variety of current injection conditions. The results predict the lateral movement of the optical field under asymmetric drive conditions which produce asymmetric variation of the complex dielectric constant of the active layer. The optical results are accompanied by the corresponding carrier and current distributions found consistently. The thesis also highlights the influence of device geometry and carrier diffusion on the optical behaviour of the device. The effect of stimulated recombination on the current spreading is also pointed out. The results show that the required modifications of the dielectric constant of the active layer to produce the near field shift and hence beam steering can be introduced by monitoring the current through the two electrodes.
Date of Award1985
Original languageEnglish
Awarding Institution
  • University of Bath

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