Spectral properties of the coherence collapsed state of a semiconductor laser with delayed optical feedback

A theoretical analysis is presented of the coherence collapsed state for a single-mode semiconductor laser with a moderate amount of delayed optical feedback and operating well above threshold. Both phase and amplitude fluctuations are taken into account, as well as the coupling between them. With the assumption that the phase fluctuations and the amplitude fluctuations satisfy a bivariate Gaussian distribution, the autocorrelation properties are determined self-consistently from the rate equations. The asymmetry of the optical power spectrum is discussed.