Waveguide Optimization for Semipolar (In,Al,Ga)N Lasers

J. Rass1, S. Ploch1, T. Wernicke1, M. Frentrup1, M. Weyers2, and M. Kneissl1,2

Published in:

Jpn. J. Appl. Phys., vol. 52, no. 08JG12 (2013).

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In this work the optical waveguiding in semipolar InGaN-based laser diodes is analyzed. Different designs of the separate confinement heterostructure with AlGaN or GaN cladding layers and GaN or InGaN waveguide layers are studied. The influence of waveguide material, thickness and composition on the optical confinement factor Γ, the accumulated strain energy E and the refractive index contrast is calculated. Measurements of the threshold and the far field intensity distributions of lasers with differing waveguide design confirm the predictions from model calculations. The optimum waveguide for a 410nm single quantum well laser is found to consist of a symmetric In0.04Ga0.96N waveguide of 2 × 85nm thickness with GaN cladding layers.

1 Technische Universität Berlin, Institut für Festkörperphysik, 10623 Berlin, Germany
2 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany