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Enhancement of optical gain by controlling waveguide modes in semipolar InGaN quantum well laser diodes
Author(s) -
Sakai Shigeta,
Matsuura Keigo,
Yamaguchi Atsushi A.
Publication year - 2017
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201600746
Subject(s) - lasing threshold , materials science , optoelectronics , waveguide , optics , laser , birefringence , polarization (electrochemistry) , refractive index , diode , quantum well , semiconductor laser theory , laser diode , physics , wavelength , chemistry
Waveguide modes in semipolar InGaN quantum‐well (QW) laser diodes (LDs) with cleaved‐facet cavity mirrors have been theoretically investigated using a 4 × 4 transfer matrix technique. It is shown that the waveguide mode can be controlled by changing the refractive‐index contrast in the waveguide structures, although previous studies suggest that the waveguide modes are either ordinary or extraordinary due to the birefringence of the material itself, and that optical gain cannot be fully utilized for lasing because the polarization direction which determines optical gain in the devices does not coincide with the polarization direction in the waveguide mode. This behavior can be explained based on the competition between the layer‐structural effect and the material birefringence. From the results of our calculations, it is concluded that the utilization of a high refractive‐index‐contrast waveguide structure is effective in enhancing the optical gain in semipolar LDs with cleaved‐facet cavity mirrors.