Microscopic model of quantum noise in single-mode semiconductor lasers - art. no. 043813

We analyze the zero-frequency intensity noise of a single-mode semiconducto r laser on the basis of a full quantum-mechanical model which takes into ac count the carrier distributions over the k states. The theory includes the effects of (i) Coulomb scattering processes, which tend to drive the carrie rs into intraband Fermi-Dirac quasiequilibrium; (ii) spectral hole burning, i.e., the carrier deviation from quasiequilibrium induced mainly by light- matter interaction; (iii) pump blocking, which, in conformity with the Paul i exclusion principle, prevents the pump carriers whose k state is already occupied from entering the active layer. Our analysis shows that Coulomb sc attering and spectral hole burning have only negligible effects on the nois e properties of the laser, while pump blocking can bring, under appropriate parametric conditions, a sizable increase of noise intensity. This additio nal noise can explain why quietly pumped semiconductor lasers fail to reach the perfect squeezing which is expected on the basis of the theory so far available. The squeezing-hindering effect of pump blocking is confirmed as different pumping schemes are employed.