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M. T. Kelemen, J. Weber, M. Rattunde, G. Kaufel, J. Schmitz, R. Moritz, M. Mikulla and J. Wagner, “High Power 1.9 μm Diode Laser Arrays with Reduced Far-Field Angle,” IEEE Photonics Technology Letters, Vol. 18, No. 4, 2006, pp. 628-630. doi:10.1109/LPT.2006.870146

has been cited by the following article:

• TITLE: Waveguide Design Optimization for Long Wavelength Semiconductor Lasers with Low Threshold Current and Small Beam Divergence

  AUTHORS: Abdulrahman Al-Muhanna, Abdullah Alharbi, Abdelmajid Salhi

  KEYWORDS: Semiconductor Laser, Far-Field, Simulation

  JOURNAL NAME: Journal of Modern Physics, Vol.2 No.4, April 22, 2011

  ABSTRACT: Long wavelength GaSb-based quantum well lasers have been optimized for high coupling efficiency into an optical system. Two approaches were used to reduce the vertical far-field. In the first approach we showed the use of V-shaped Weaker Waveguide in the n-cladding layer dramatically reduces vertical beam divergence without any performance degradation compared to a conventional broad-waveguide laser structure. Starting from a broad waveguide laser structure design which gives low threshold current and a large vertical far-field (VFF), the structure was modified to decrease the VFF while maintaining a low threshold-current density. In a first step the combination of a narrow optical waveguide and reduced refractive index step between the waveguide and the cladding layers reduce the VFF from 67? to 42?. The threshold current density was kept low to a value of ~190 A/cm2 for 1000 × 100 µm2 devices by careful adjustment of the doping profile in the p-type cladding layer. The insertion of a V-Shaped Weaker Waveguide in the n-cladding layer is shown to allow for further reduction of the VFF to a value as low as 35? for better light-coupling efficiency into an optical system without any degradation of the device performance. In the second approach, we showed that the use of a depressed cladding structure design also allows for the reduction of the VFF while maintaining low the threshold current density (210 A/cm2), slightly higher value compare to the first design.