Factors influencing brightness and beam quality of conventional and distributed Bragg reflector tapered laser diodes in absence of self-heating

• Published in: IET optoelectronics Vol. 8; no. 2; pp. 99 - 107
• Main Authors: Kaunga-Nyirenda, Simeon Newton, Bull, Stephen, Lim, Jun Jun, Hasler, Karl-Heinz, Fricke, Jörg, Larkins, Eric C
• Format: Journal Article
• Language: English
• Published: Stevenage The Institution of Engineering and Technology 01.04.2014; The Institution of Engineering & Technology
• Subjects: Angle of reflection; beam quality; Beams (radiation); beamspoiler; Bragg reflectors; Brightness; carrier lensing; Carriers; DBR tapered lasers; distributed Bragg reflector tapered laser diodes; front facet reflectivity; laser beams; laser modes; Lasers; multimode operation; optical resonators; optical waveguides; Reflectivity; ridge waveguide; ridge waveguides; Ridges; semiconductor lasers; Special Issue on Semiconductor Lasers and Integrated Optoelectronics; taper angle; volume resonators; carrier lensing; laser modes; volume resonators; beam quality; optical waveguides; optical resonators; taper angle; reflectivity; distributed Bragg reflector tapered laser diodes; front facet reflectivity; brightness; ridge waveguides; ridge waveguide; laser beams; DBR tapered lasers; semiconductor lasers; multimode operation; beamspoiler
• ISSN: 1751-8768; 1751-8776; 1751-8776
• DOI: 10.1049/iet-opt.2013.0082

In this study, the authors examine some of the factors affecting the brightness and the beam quality of high-power tapered lasers. The large volume resonators required to achieve high-power, high-brightness operation make the beam quality sensitive to carrier lensing and multimode operation. These cause bleaching of the regions outside the ridge waveguide. The beam quality in the conventional and the distributed Bragg reflector tapered lasers is examined in the absence of the self-heating effects in order to investigate the impact of the carrier lensing effects. The influence of the front facet reflectivity and the taper angle on the beam quality is investigated. The beam quality was found to degrade with an increase in the front facet reflectivity and for larger taper angles in the conventional tapered lasers, especially at low ridge waveguide currents. Finally, the performance of conventional tapered lasers employing a beamspoiler was assessed. The beam quality was found to be comparable with that achieved in the DBR tapered lasers.