Dynamics of thermo-optical properties of semiconductor lasers

In the paper, the dynamics in the microsecond time-range of thermally induced wavelength shifts in emission spectra of pulse operated semiconductor lasers is studied. The experimental technique of time-resolved laser spectra mapping, developed to assess thermo-optical properties of pulse operating lasers is described. The presented technique enables measurements of the laser mode spectral characteristics at an arbitrarily selected moment within the duration of driving current pulse. The measured shift of the dominant mode wavelength in the spectrum envelope enables to find out temperature change of the laser active region. The values of the temperature change have been compared with the ones numerically calculated employing the finite element method.