Real Life Examples

Specific Examples

The use of SimuLase™ for the typical example of an edge-emitter and a VECSEL are described in the examples guide.

Below are some comparisons between experimental results and those of the fully microscopic calculations done with SimuLase™ for an:

  • InGaAsP-based edge-emitter operating at 1.3µm,
  • InGaAs-based VECSEL operating at 1.04µm,

Carrier losses and resulting threshold currents in an:

  • InGaSb/InAs/AlGaSb type-II ‘W’ structure operating at 3.4µm,
  • InGaAsP/InP-structure operating at 1.3µm,
  • InGaAs/InP-structure operating at 1.5µm,
  • GaInNAs/GaAs-structure operating at 1.3µm

And some more examples for

  • Gain in an InGaN/GaN multi quantum well,
  • Gain in an GaInNAs/GaAs multi quantum well,
  • Gain and LWEF in an InGaAs/AlGaAs GRINSCH,
  • Gain in an InGaAs/AlGaAs SCH,
  • Absorption in an InGaAs/InP superlattice.

More examples can be found in the news section.

Edge Emitter and VECSEL

A detailed explanation on how to use SimuLase™ for the examples of an edge emitting ridge waveguide structure and a VECSEL structure, including theory-experiment comparisons for all important aspects, ranging from the PL to the input-output characteristics, can be found here.
The edge emitting example is based on Ref. [30], the VECSEL example is based on Ref. [41].

Screen grabs from SimuLase in the analysis of an edge-emitting structure

Screen grabs from VECSEL

InGaSb/InAs/AlGaSb ‘W’ structure for 3.4µm

Experimentally measured (solid lines) and calculated (dashed lines) temperature-dependent PL spectra for a mid-infrared type-II ‘W’ diode lase structure operating near 3.4µm at room temperature. The active region consists of a short superlattice of five InAs/GaInSb/InAs/AlGaSb wells.

 

Temperature-dependent threshold current density for the mid-infrared type-II ‘W’ diode lase structure. Dots: Experimental data. Solid line: Total theoretical loss current. Dashed line: Calculated Auger loss current. Dotted line: Calculated radiative loss current.

For more details on this example and calculations for radiative and Auger losses see Ref. [40].

Loss in an InGaAsP/InP-structure for 1.3µm

Experimentally measured (black signs) and calculated (thick lines) temperature-dependent loss currents at threshold for a structure containing eight 4.4nm wide In0.83Ga0.17As0.67P0.33/InP quantum wells lasing near 1.3µm. The experimental data was extracted from A.F. Phillips, et al., IEEE J. Sel. Topics Quantum Electron., vol. 5, 401 (1999). Black: total loss current; Red: radiative loss current due to spontaneous emission; Blue: Auger loss current.

For more details on this example and calculations for radiative and Auger losses see Ref. [28].

Loss in an InGaAsP/InP-structure for 1.5µm

Experimentally measured (black signs) and calculated (thick lines) temperature-dependent loss currents at the threshold for a structure containing four 2.5nm wide In0.65Ga0.35As/InP quantum wells lasing near 1.5µm. The experimental data was extracted from A.F. Phillips et al., IEEE J. Sel. Topics Quantum Electron., vol. 5, 401 (1999). Black: total loss current; Red: radiative loss current due to spontaneous emission; Blue: Auger loss current.

For more details on this example and calculations for radiative and Auger losses, see Ref. [28].

Loss in a GaInNAs/GaAs-structure for 1.3µm

Experimentally measured (thin lines and signs) and calculated (thick lines) temperature-dependent loss currents at threshold for a structure with a 6.4nm wide Ga0.66In0.34N0.018As0.982/GaAs quantum well lasing near 1.3µm. The experimental data was extracted from R. Fehse, et al., IEEE J. Sel. Topics Quantum Electron., vol. 8, 801 (2002). Black: total loss current; Red: radiative loss current due to spontaneous emission; Blue: Auger loss current. Losses due to defect recombination have been excluded from the shown experimental data. The deviations between theory and experiment at high temperatures are probably due to internal heating beyond the heat sink temperature.

For more details on this example and calculations for radiative and Auger losses see Ref. [28].

Gain in InGaN/GaN

Experimentally measured (black signs) and calculated (red lines) gain spectra for a structure containing of 2nm wide In0.1Ga0.9N quantum wells between 6nm wide GaN barriers. The experimental data was extracted from B. Witzigmann, et al., Appl. Phys. Lett., 88, 021104 (2006).

For more details on this example and calculations for wide bandgap nitride systems see Ref. [31] and Ref.[32].

Gain in GaInNAs/GaAs

Experimentally measured (blue signs) and calculated (red lines) modal gain spectra for a structure consisting of three 6nm wide In0.32Ga0.68N0.01As0.99 quantum wells between In0.05Ga0.95N0.015As0.985 barriers. The experimental data were obtained with the Hakki-Paoli method.

The sheet carrier densities in the calculations ranged from 3.75 to 8.25×10¹²/cm² with increments of 0.75×10¹²/cm², the injection currents in the experiment were 7, 12, 14, 16 and 18mA.

For more details see Ref. [1].

Gain spectra for the same structure as above but for a wider density range. It demonstrates the heating of the device under high excitation conditions, leading to an otherwise unusual red shift of the spectra. The comparison can be used to determine internal temperatures and heating. The experimental data was obtained with a different method than in the example above, which allows to examine a wider density range, but is less accurate. Blue: experimental results for 0, 5, 10, 15, 20, 30, 40, 50, 60 and 70mA. Red: theoretical results for the assumed temperature of 300K and densities of 0, 1.5, 2.5, 3.0, 3.5 and 6.0×10¹²/cm². Green: theoretical results for 312K and 4.5 and 5.0×10¹²/cm². Magenta: 325K, 7.0*10¹²/cm². Black: 337K and 9.0×10¹²/cm².

For more details see Ref. [14].

Gain and LWEF in InGaAs/AlGaAs-GRINSCH

Experimentally measured (blue signs) and calculated (red lines) modal gain spectra for a structure containing a 10nm wide In0.2Ga0.8As quantum well between 85nm wide AlxGa1-xAs graded index barriers where the Aluminium concentration rises linearly from x=0.1 to x=0.6 with distance from the well.
 
Experimentally measured (blue signs) and calculated (red lines) linewidth enhancement factors (alpha factors, LWEF) for the structure above and for one with a smaller well width of only 5nm. The LWEF is taken at the spectral position of the gain maximum.

For more details see Ref. [2].

Gain in InGaAs/AlGaAs-SCH

Theory-experiment comparison for a structure consisting of a 8nm wide In0.05Ga0.95As quantum well between Al0.2Ga0.8 barriers. Blue signs show the experimental results, red lines the theoretical ones. The carrier densities in the theory ranged from 0.6 to 3.0×10¹²/cm². The experimental currents are from 0 to 20mA.

For more details see Ref. [3].

Absorption in GaInAs/InP-Superlattice

Theory-experiment comparison for the excitonic absorption in a system of electronically coupled InGaAs quantum wells that are separated by thin InP barriers (‘superlattice’) under different external electric fields.

For the case of a field of 44 kV/cm the red dashed line shows the theoretical result if the conduction band nonparabolicity is neglected. The red solid lines have been calculated with this nonparabolicity. The lines for different fields have been shifted along the absorption axis for better clearity.

For more details see Ref. [5].

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