Single-mode monolithic GaSb Vertical-Cavity Surface-Emitting Laser.

Area of Science:

• Optoelectronics
• Semiconductor Lasers
• Materials Science

Background:

• Vertical-Cavity Surface-Emitting Lasers (VCSELs) are crucial optoelectronic devices.
• Gallium Antimonide (GaSb)-based materials offer unique properties for infrared applications.
• Monolithic integration of VCSELs with high performance remains a key challenge.

Purpose of the Study:

• To report the fabrication and performance of an electrically-pumped Gallium Antimonide (GaSb) monolithic Vertical-Cavity Surface-Emitting Laser (VCSEL).
• To demonstrate single-mode operation and electro-thermal tunability in a monolithic GaSb VCSEL.

Main Methods:

• Fabrication of a monolithic GaSb VCSEL utilizing two epitaxial Bragg mirrors.
• Implementation of selective lateral etching of a tunnel junction for current and optical confinement.
• Characterization of laser performance, including threshold current, continuous-wave (CW) operation, and spectral properties.

Main Results:

• The GaSb VCSEL operates at 2.3 µm in CW up to 70 °C.
• Devices exhibit a low threshold current of 1.9 mA at 30 °C.
• Single-mode emission with a side-mode suppression ratio (SMSR) near 25 dB was achieved.
• Mode-hop-free electro-thermal tunability of approximately 14 nm was demonstrated.

Conclusions:

• This work presents the first demonstration of a single-mode, electrically-pumped monolithic GaSb-based VCSEL.
• The developed GaSb VCSEL shows promising performance for infrared applications.
• The fabrication technique enables efficient current and optical confinement for high-performance VCSELs.