Specific features of the VCSEL spectra under microwave current modulation

Area of Science:

• Optics and Photonics
• Semiconductor Lasers

Background:

• Vertical-cavity surface-emitting lasers (VCSELs) exhibit asymmetric optical spectra under microwave frequency current modulation.
• Conventional explanations involving amplitude and phase modulation do not fully account for this observed asymmetry.

Purpose of the Study:

• To develop a more comprehensive understanding of spectral asymmetry in modulated VCSELs.
• To investigate the nonlinear interactions within the laser field components.
• To identify new spectral features and their dependence on injection current.

Main Methods:

• Sequential analysis based on Maxwell's equations.
• Accounting for nonlinear interactions among five spectral components of the laser field.
• Experimental verification of predicted spectral features.

Main Results:

• The developed model predicts a non-global asymmetry in the optical spectrum.
• A novel resonant feature was identified in the power ratio of the second sidebands.
• Experimental results confirmed the model's predictions, including the resonant feature.

Conclusions:

• The nonlinear interaction of spectral components provides a more complete explanation for VCSEL spectral asymmetry.
• The study introduces a new perspective on understanding laser dynamics under modulation.
• Experimental validation highlights the practical implications for laser design and application.