POLARIZATION FLUCTUATIONS DEMONSTRATE NONLINEAR ANISOTROPY OF A VERTICAL-CAVITY SEMICONDUCTOR-LASER

We report observation of polarization fluctuations in vertical-cavity semiconductor lasers, which allows us to demonstrate and quantify the importance of nonlinear polarization anisotropy. We focus on three asp ects, which all fit within the same theoretical framework: (i) a nonli near spectral redshift, (ii) an extra four-wave mixing peak in the opt ical spectrum, and (iii) correlations between the polarization fluctua tions.