Title :
Circular grating-coupled surface-emitter with high-quality focused output beam
Author :
Kristjánsson, Sigurgeir ; Eriksson, Niklas ; Sheard, Steve J. ; Larsson, Anders
Author_Institution :
Dept. of Microelectron., Chalmers Univ. of Technol., Goteborg, Sweden
fDate :
5/1/1999 12:00:00 AM
Abstract :
We have investigated the effect of resonator size and geometry on the performance of focusing circular grating-coupled surface-emitting lasers. Both the effects of reducing the resonator diameter and introducing an unpumped indentation in the center of the resonator have been studied. We have found that inclusion of such an unpumped central indentation can greatly improve the spatial-mode behavior, resulting in a very uniform near-field intensity, single wavelength emission, and a focused spot size only 1.5 times the diffraction limit for a laser oscillating in the fundamental circular mode. Reducing the resonator diameter of lasers without an unpumped central indentation does not offer similar improvement.
Keywords :
diffraction gratings; laser beams; optical couplers; optical focusing; semiconductor lasers; surface emitting lasers; circular grating-coupled surface-emitter; diffraction limit; focused spot size; focusing circular grating-coupled surface-emitting lasers; high-quality focused output beam; resonator diameter; resonator geometry; resonator size; single wavelength emission; spatial-mode behavior; unpumped central indentation; unpumped indentation; very uniform near-field intensity; Gratings; Laser beams; Laser feedback; Laser modes; Laser theory; Optical resonators; Optical surface waves; Semiconductor laser arrays; Semiconductor lasers; Surface emitting lasers;
Journal_Title :
Photonics Technology Letters, IEEE
