Trends of research

Development of the injection heterolasers for visible and near infrared spectral range with improved performances

Study of the physical processes occurring in the active field of semiconductor lasers and simulation of the radiation parameters of quantum-well heterolasers; creation of a software to calculate the:

• distribution of a field intensity inside the laser cavity
• intensity distribution in the far field of laser radiation
• light-current characteristics of the laser
• dependence of material gain and refractive index of the active field on the concentration of injected carriers
• phase noise and intensity fluctuations of laser radiation
• self-fluctuation intensities of laser radiation with a ridge waveguide

The engineering of a waveguide structure of laser resonator and simulation of radiation parameters for the new type heterolasers with a quantum-well active region:

• the high-power and high-brightness heterolasers with a ridge waveguide
• the lasers with a reduced divergence of the optical beam, including the lasers operating on derived modes
• the α-DFB – lasers

The experimental measurement of material parameters of quantum-well heterolasers:

• a spectral gain contour
• a differential gain
• the coefficient of the phase - amplitude relation (α-factor)
• the optical losses

The simulation of heterolaser radiation parameters can be realized by solving a problem of electromagnetic wave propagation and amplification in the developing heterolaser design.
To solve this problem it is necessary to know the electromagnetic geometrical parameters of the structure (the layers thickness and width and a cavity length) and its material parameters, namely, complex permittivity values of the structure layers (a refractive index, the index of gain / absorption).

For passive layers of the structure these data, in most cases, can be taken from the scientific articles. Their values for a specific structure weakly depend on the operating laser mode.
In contrast, the material parameters of the active heterolaser layers strongly depend on its operating point, and this dependence is not the universal one. Thus, in most cases they cannot be taken from the articles. Theoretical calculations of these parameters for the active laser fields in different operating modes do not provide the necessary accuracy.
All the abovementioned leads to the fact that the most reliable way to develop a new laser design is to carry out the related experimental measurements of the listed material parameters.

Characterization of the heterolasers under developing:

• measurements of the light-current characteristics, intensity distributions in the near and far radiation fields
• measurement of the M² factor (characterizing a radiation brightness)
• measurement of the radiation coherency and a spectral width  
• a high-brightness laser research, including two-dimensional laser arrays
• study  of the catastrophic optical degradation of powerful laser mirrors

The purpose of the experimental measurements:

- Verification and comparison of the simulation results of a
developed laser resonator structure to the real parameters
of the produced samples

- Elaboration of recommendations to adjust the
  developed laser parameters and, possibly,
   to adjust the simulation process