Very low threshold current operation of semiconductor ring lasers

Author

Krauss, T. ; Laybourn, P.J.R.

Author_Institution

Dept. of Electron. & Electr. Eng., Glasgow Univ., UK

Volume

139

Issue

6

fYear

1992

fDate

12/1/1992 12:00:00 AM

Firstpage

383

Lastpage

388

Abstract

Semiconductor ring lasers with a threshold current as low as 12.5 mA have been fabricated in GaAs/AlGaAs. The low threshold current is due to a passivating layer of silicon nitride and an optimised fabrication process that results in very smooth sidewalls. The threshold current was analysed and it was found that a considerable part of the current is lost by spreading towards the inside of the pillbox structure. The remaining loss mechanisms were identified as internal loss (1 dB), coupling loss (7-8 dB) and scattering loss (2-4 dB). The scattering loss was found to be independent of the radius for radii between 30 μm and 145 μm. The L-I curve displays several kinks, which are explained by shifts of the mode position and thus the coupling ratio at the Y-junction due to temperature changes with pumping

Keywords

III-V semiconductors; aluminium compounds; gallium arsenide; light scattering; optical losses; ring lasers; semiconductor lasers; 1 dB; 12.5 mA; 2 to 4 dB; 60 to 290 micron; 7 to 8 dB; GaAs-AlGaAs; L-I curve; Si₃N₄; Y-junction; coupling loss; coupling ratio; internal loss; loss mechanisms; mode position shifts; optimised fabrication process; passivating layer; pillbox structure; pumping; scattering loss; semiconductor ring lasers; temperature changes; very low threshold current operation; very smooth sidewalls;

fLanguage

English

Journal_Title

Optoelectronics, IEE Proceedings J

Publisher

iet

ISSN

0267-3932

Type

jour

Filename

180093