High power and good beam quality of two-dimensional VCSEL array with integrated GaAs microlens array

Area of Science:

• Semiconductor lasers
• Optoelectronics
• Materials science

Background:

• Vertical-cavity surface-emitting lasers (VCSELs) are crucial optoelectronic devices.
• Achieving high power and good beam quality in two-dimensional VCSEL arrays remains a challenge.
• Integrated optics can enhance VCSEL performance.

Purpose of the Study:

• To develop a high-power, good beam quality two-dimensional bottom-emitting VCSEL array.
• To investigate the effect of integrated GaAs microlenses on VCSEL performance.
• To demonstrate the advantages of microlens-integrated VCSELs over conventional devices.

Main Methods:

• Fabrication of uniform convex GaAs microlenses on emitting windows using one-step diffusion-limited wet-etching.
• Integration of microlenses onto a two-dimensional bottom-emitting VCSEL array structure.
• Characterization of output power and far-field beam divergence at various operating currents.

Main Results:

• Achieved maximum output power exceeding 1 W under continuous-wave operation at room temperature.
• Demonstrated far-field beam divergence below 6.6° at a current of 4 A.
• Quantified performance improvements in microlens-integrated VCSELs compared to conventional devices.

Conclusions:

• One-step diffusion-limited wet-etching is an effective technique for fabricating high-quality GaAs microlenses.
• Integrated microlenses significantly enhance the beam quality and power output of VCSEL arrays.
• The developed microlens-integrated VCSELs show great potential for high-power, high-brightness applications.