Selective TE-TM mode pumping efficiencies for ridge-waveguide lasers in presence of stress

In ridge-waveguide InGaAsP lasers, TE-TM polarization switching with injection current can be caused by the presence of stress in the active layer coming from the deposition of stressed oxide and metallic films on the surface. It is shown that polarization switching takes its origin in the change of the mode pumping efficiency as the current varies. This conclusion has been reached with the help of a comprehensive semiconductor laser model that includes stress effects. Various stress regimes have been identified and it is also shown that the overall stress value in the active layer is the dominant effect, not so much the detailed stress profile.<>