Analysis of mode broadening due to transient heating of optically pumped semiconductor lasers

We have found that the output spectra of cleaved semiconductor lasers are broadened when they are optically excited with a high-energy pulsed laser. We believe the effect is due to transient heating. A one-dimensional heat-flow equation has been solved, and the results are applied to two representative cases, GaAs and PbTe. Good agreement is obtained between the calculated broadening and the experimentally observed values.