Single-mode surface-emitting microcylinder/microring laser assisted by a shallowly-etched top grating

Area of Science:

• Optoelectronics
• Photonics
• Semiconductor Devices

Background:

• Microcylinder/microring semiconductor lasers offer high-quality factor modes for optical interconnects.
• Existing designs suffer from multi-mode lasing and non-directional emission, limiting practical applications.

Purpose of the Study:

• To propose and demonstrate a single-mode, surface-emitting laser at the O-band.
• To overcome the limitations of multi-mode lasing and non-directional emission in microcavity lasers.

Main Methods:

• Fabrication of a second-order grating shallowly etched on a microcylinder/microring cavity.
• Electrical pumping for continuous wave (CW) operation.
• Characterization of lasing mode, emission directionality, and performance over a temperature range.

Main Results:

• Achieved single-mode lasing with a side-mode suppression ratio (SMSR) > 40 dB.
• Demonstrated upward surface emission with optical power exceeding 1 mW.
• Continuous wave operation maintained over a wide temperature range.

Conclusions:

• The proposed second-order grating effectively enables single-mode operation and vertical surface emission.
• This laser design is a promising candidate for optical interconnects and can be adapted for other communication bands (C-band, L-band).