Semiconductor lasers with a thin active layer (>0.1 microm for optical communications

Area of Science:

• Optoelectronics
• Semiconductor Lasers
• Optical Communications

Background:

• Double heterostructure lasers are crucial light sources for optical communication systems.
• Optimizing device parameters, particularly active layer thickness, is essential for enhanced performance.
• Previous research has explored various configurations, but specific parameter optimization for thin active layers remains key.

Purpose of the Study:

• To investigate double heterostructure lasers with thin active layers.
• To optimize device parameters for enhanced performance as light sources in optical communication systems.
• To determine the optimal active layer thickness for minimizing threshold current density and maximizing coupling efficiency.

Main Methods:

• Theoretical investigation and simulation of double heterostructure laser diodes.
• Systematic variation of active layer thickness to analyze its impact on device characteristics.
• Measurement and analysis of threshold current density, beam divergence, and optical fiber coupling efficiency.

Main Results:

• A minimum threshold current density was observed for an active layer thickness of approximately 800 Angstroms in undoped active layers.
• For active layer thicknesses below 0.1 micrometers, the full width of beam divergence was less than 30 degrees.
• An average coupling efficiency of 50% and a maximum of 80% into a low numerical aperture (0.05) optical fiber was achieved, especially with a focusing lens.

Conclusions:

• Thin active layers in double heterostructure lasers are critical for achieving low threshold current density and desirable beam characteristics.
• The optimal active layer thickness of around 800 Angstroms significantly enhances performance for optical communication applications.
• These findings provide valuable insights for designing efficient laser diodes for high-performance optical communication systems.