UV Laser Diode

UV Laser Diode on sapphire substrate (example includes project files)

Figure 1 Typical Waveguide Modes

Starting year 2007, SiLENSe releses included special features
for simulation of laser diodes.

In SiLENSe package, simulation of the Laser Diode operation can be carried
out with the account of both the carrier transport in the heterostructure
and electromagnetic wave propagation, which, combined with the main
functionality of the SiLENSe simulator.

It is particularly important that modeling of TE-
and TM-modes in the waveguide includes account for (i) birefringence inherent
in III-nitride materials and (ii) metallic electrodes on top of the Laser Diode
structure, since the difference between the ordinary and extraordinary
refractive indexes is comparable with their variation across the heterostructure.

The example presented is dedicated to explaining these features
and demonstrating some results obtained using the SiLENSe Laser Edition.

Figure 2 Threshold current variation with the oscillation
wavelength. Red line stands for simulation, blue dots represent experimental data

Generally, simulation with SiLENSe Laser Edition includes the following steps:

  • computation of the band diagram, carrier transport,
    radiative and non-radiative recombination rates;
  • computation of the carrier energy levels and wave functions;
  • computation of the waveguide TE- and TM- modes, including advanced
    approximation of the refractive index dispersion in nitride materials and account
    for birefringence;
  • computation of the optical gain and losses including computation
    of the gain spectrum and optical confinement factor for each quantum well and
    optical losses caused by the free carriers;
  • calculation of total optical loss as a sum of mirror losses
    and losses caused by free carrier absorption;
  • computation of threshold current density as a current at which
    modal gain becomes equal to the total optical loss;
  • calculation of differential quantum efficiency.

Comparison of computations with the experimental data by M. Kneissl et.al.,
APL 82, 2386 (2003), is shown in Figure 2. Wavelength of 363-380 nm is controlled
by variation of the In composition in QWs up to 4%.

More detailed discussion of the results can be found in preprint of our publication

Effects of electron and optical confinement on performance of
UV laser diodes
, follow the link to read the article.

This example is accompanied by the set of project files, that allow license holders to reproduce
all the computations used to illustrate this example. If you do not have a license, you can
either request one, (mark.ramm@str-soft.com)
or use the same project files to see how settings for these computations can be defined
in the SiLENSe graphical user interface. To download the project files, please,
visit SiLENSe section at

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