Electrically injected VCSEL with a composite DBR and MHCG reflector

Area of Science:

• Optics and Photonics
• Semiconductor Devices

Background:

• Traditional vertical-cavity surface-emitting lasers (VCSELs) often rely on complex multilayer dielectric Bragg reflectors (DBRs).
• Existing high-refractive-index-contrast gratings (HCGs) typically require suspended membranes or cladding layers, adding manufacturing complexity.

Purpose of the Study:

• To demonstrate continuous-wave (CW) lasing in electrically injected VCSELs utilizing a novel subwavelength monolithic high-refractive-index-contrast grating (MHCG) mirror.
• To present an all-semiconductor laser architecture that simplifies fabrication and reduces vertical thickness.

Main Methods:

• Fabrication of VCSELs incorporating a subwavelength monolithic high-refractive-index-contrast grating (MHCG) mirror directly patterned in the semiconductor atop the laser cavity.
• Static characterization of the fabricated VCSELs under continuous-wave operation.

Main Results:

• Achieved continuous-wave (CW) lasing operation in electrically injected VCSELs with the MHCG mirror.
• Demonstrated stable quasi-single mode emission from threshold to rollover for a 13.5 μm aperture device.
• Confirmed CW operation up to 75 °C.

Conclusions:

• The developed MHCG mirror enables the creation of all-semiconductor VCSELs without suspended membranes or cladding layers.
• This technology offers a pathway to significantly reduced vertical thickness and potentially up to 90% cost reduction compared to DBR VCSELs.
• The all-semiconductor VCSELs are suitable for diverse applications including optical communication, illumination, sensing, and photonic integrated circuits across UV, visible, and infrared wavelengths.