Polarization mode control of long-wavelength VCSELs by intracavity patterning

Area of Science:

• Optoelectronics
• Laser Physics
• Materials Science

Background:

• Vertical-cavity surface-emitting lasers (VCSELs) are key components in optical communication systems.
• Controlling polarization mode is crucial for stable laser operation and high-speed data transmission.
• Existing methods for polarization control in 1310 nm VCSELs have limitations.

Purpose of the Study:

• To enhance polarization mode control in wafer-fused VCSELs operating at 1310 nm.
• To investigate the effect of intracavity patterning on VCSEL polarization dynamics.
• To improve the stability and performance of VCSELs for optical applications.

Main Methods:

• Fabrication of wafer-fused VCSELs with symmetrically arranged etched arcs within the laser cavity.
• Introduction of birefringence and dichroism through intracavity patterning.
• Experimental measurement of polarization angle, gain anisotropy, and polarization switching current.
• Analysis using the spin-flip model of VCSEL polarization dynamics.

Main Results:

• Etched arcs effectively introduced birefringence and dichroism, discriminating between polarization states.
• Cavity modifications determined the polarization angle at threshold relative to crystal axes.
• Increased gain anisotropy and birefringence were observed on average.
• A significant increase in polarization switching current was achieved, indicating enhanced control.

Conclusions:

• Symmetrical intracavity patterning is an effective method for enhancing polarization mode control in 1310 nm VCSELs.
• The spin-flip model accurately explains the observed polarization dynamics.
• This technique offers a promising approach for developing more stable and reliable VCSELs for advanced optical communication.