Stokes parameters of the radiation of transverse-single-mode InGaAs/AlGaAs lasers with a quantum-well active region

A study of lasers with two different heterostructures has revealed that the polarisation state of laser radiation depends strongly on the specific sample at pump currents corresponding to the regular behaviour of the light—current characteristic. Thus, the deviation of the radiation polarisation from linear can be used as a sensitive characteristic of the laser quality. It is found that anomalies in the power—current characteristic (the so-called kinks) are accompanied by a significant decrease in the degree of polarisation. The measured degrees of polarisation of spontaneous emission from samples (at pump currents much below the threshold) are in good agreement with the theoretical estimate obtained within the three-band model of optical transitions.