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Advances in OptoElectronics
Volume 2019, Article ID 2719808, 7 pages
Research Article

1D Confocal Broad Area Semiconductor Lasers (Confocal BALs) for Fundamental Transverse Mode Selection (TMS#0)

Integrated Optoelectronics and Microoptics Research Group, Physics Department, Technische Universität Kaiserslautern (TUK), P.O. Box 3049, D-67653 Kaiserslautern, Germany

Correspondence should be addressed to Henning Fouckhardt;

Received 11 March 2019; Accepted 16 April 2019; Published 17 June 2019

Academic Editor: Vasily Spirin

Copyright © 2019 Henning Fouckhardt et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Previously in this journal we have reported on fundamental transverse mode selection (TMS#0) of broad area semiconductor lasers (BALs) with integrated twice-retracted 4f set-up and film-waveguide lens as the Fourier-transform element. Now we choose and report on a simpler approach for BAL-TMS#0, i.e., the use of a stable confocal longitudinal BAL resonator of length L with a transverse constriction. The absolute value of the radius R of curvature of both mirror-facets convex in one dimension (1D) is R = L = 2f with focal length f. The round trip length 2L = 4f again makes up for a Fourier-optical 4f set-up and the constriction resulting in a resonator-internal beam waist stands for a Fourier-optical low-pass spatial frequency filter. Good TMS#0 is achieved, as long as the constriction is tight enough, but filamentation is not completely suppressed.