Engineering the Lateral Optical Guiding in Gallium Nitride (GaN)-based Vertical-Cavity Surface-Emitting Laser (VCSEL) Cavities to Reach the Lowest Threshold Gain
Journal article, 2013

In order to improve the current injection in GaN-based blue vertical-cavity surface-emitting lasers (VCSELs) a dielectric aperture is generally used in combination with an indium–tin-oxide (ITO) layer on the top intracavity p-contact layer. The most straightforward way to realize this introduces a depression of the structure near the optical axis and we show, by using a two-dimensional (2D) effective index method and a three-dimensional (3D) coupled-cavity beam propagation method, that this typically results in optically anti-guided structures with associated high optical losses and thus very high threshold gains. Remarkably, the threshold gain reduces with increased negative guiding, which is due to improved lateral confinement and reduction of lateral leakage. Still, moderately positively guided designs should be preferred to avoid the detrimental effect of lateral leakage and high diffraction loss. To ensure positive index guiding, we propose to planarize the structure or introduce an elevation near the optical axis by additional processing, with an associated reduction in threshold material gain from 6000 to 2000 cm-1 for the studied structures.

Gallium-Nitride

Blue VCSEL

Anti-guiding

Guiding

GaN-based microcavities

Author

Seyed Ehsan Hashemi

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Johan Gustavsson

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Jörgen Bengtsson

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Martin Stattin

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Gatien Cosendey

Ecole Polytechnique Federale De Lausanne

Nicolas Grandjean

Ecole Polytechnique Federale De Lausanne

Åsa Haglund

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Japanese Journal of Applied Physics

0021-4922 (ISSN)

Vol. 52 8 PART 2 08JG04 -

Areas of Advance

Nanoscience and Nanotechnology (2010-2017)

Subject Categories

Telecommunications

Nano Technology

Condensed Matter Physics

Infrastructure

Nanofabrication Laboratory

DOI

10.7567/JJAP.52.08JG04

More information

Latest update

5/3/2018 1