Modeling thermal effects and polarization competition in vertical-cavity surface-emitting lasers

Area of Science:

• Optoelectronics
• Semiconductor Lasers
• Thermal Physics

Background:

• Vertical-cavity surface-emitting lasers (VCSELs) are key components in optical communication and sensing.
• Understanding their operational characteristics under varying temperatures is crucial for reliable performance.
• Thermal effects can significantly influence laser output power, wavelength, and polarization behavior.

Purpose of the Study:

• To analyze the influence of thermal effects on the polarization-resolved light-current (LI) characteristics of VCSELs.
• To develop and utilize a comprehensive model that incorporates temperature-dependent gain, cavity resonance, and heating mechanisms.
• To investigate the temperature sensitivity of key VCSEL parameters like threshold current and polarization switching.

Main Methods:

• An extended spin-flip model was employed, incorporating frequency and temperature-dependent material gain.
• A rate equation for the active region temperature was included, accounting for heat dissipation and generation (Joule heating, nonradiative recombination).
• The model incorporated the red shift of gain curves and cavity resonance with increasing temperature.

Main Results:

• The temperature sensitivity of the lasing threshold current demonstrated good qualitative agreement with experimental observations and previous theoretical models.
• The temperature dependence of the polarization switching point was successfully characterized.
• The study identified key model parameters influencing polarization switching, including gain-cavity offset, substrate temperature, and active region size.

Conclusions:

• The developed model provides a robust framework for understanding thermal effects on VCSEL LI characteristics.
• Accurate prediction of temperature-dependent threshold current and polarization switching is achievable.
• The findings offer valuable insights for designing and optimizing VCSELs for stable operation across different thermal environments.