Impact of output coupler configuration on operating characteristics of semiconductor ring lasers

Author

Krauss, T.F. ; De La Rue, R.M. ; Laybourn, P.J.R.

Author_Institution

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

Volume

13

Issue

7

fYear

1995

fDate

7/1/1995 12:00:00 AM

Firstpage

1500

Lastpage

1507

Abstract

We have investigated semiconductor (GaAs/AlGaAs) ring lasers with three different types of output coupler in order to identify the influence of the coupling geometry on the performance of such lasers. Ring lasers with multimode interference (MMI) couplers show significantly better characteristics than devices with Y-junctions and directional couplers. This improvement is explained by the high tolerance of MMI couplers to changes in the position of the input field, the refractive index and the operating wavelength that occur through changes in device operation. The work was also motivated by the need to improve the currently poor efficiency of ring laser devices and several ways of achieving improvement have arisen from the present investigation. All of the devices investigated had a bend radius of 400 μm, the resonator length was between 2.5 mm and 3.2 mm and a strip-loaded waveguide geometry was used. The lowest threshold current obtained was 80 mA in a device with a directional coupler, and the highest differential quantum efficiency achieved was 8%, using a 280-μm-long MMI coupler

Keywords

III-V semiconductors; aluminium compounds; gallium arsenide; laser cavity resonators; optical couplers; optical directional couplers; refractive index; ring lasers; semiconductor lasers; 2.5 to 3.2 mm; 280 mum; 8 percent; 80 mA; 800 mum; GaAs-AlGaAs; GaAs/AlGaAs; Y-junctions; bend radius; coupling geometry; device operation; directional coupler; directional couplers; high tolerance; highest differential quantum efficiency; input field; lowest threshold current; multimode interference couplers; operating characteristic; operating wavelength; output coupler; output coupler configuration; poor efficiency; refractive index; resonator length; ring laser devices; semiconductor ring lasers; strip-loaded waveguide geometry; Directional couplers; Gallium arsenide; Geometrical optics; Interference; Optical coupling; Refractive index; Ring lasers; Semiconductor lasers; Threshold current; Waveguide lasers;

fLanguage

English

Journal_Title

Lightwave Technology, Journal of

Publisher

ieee

ISSN

0733-8724

Type

jour

DOI

10.1109/50.400718

Filename

400718