THEORY OF LASER-DIODES WITH WEAK OPTICAL FEEDBACK .1. SMALL-SIGNAL ANALYSIS AND SIDE-MODE SPECTRA

The properties of a single-mode semiconductor laser with weak optical feedback from a distant reflector are modeled by Langevin equations for the plasma density and for a classical electric field. A novel comprehensive small-signal analysis of the deterministic model equations is performed near their stationary solution. The modifications of the relaxation oscillations between carrier and photon densities that are caused by the optical feedback are studied. Spectral properties are calculated by adding Langevin fluctuation terms of the dissipative processes. New analytic approximations for the dominant contributions to the time-averaged field autocorrelation spectrum are derived and compared with the results for a free-running laser.