On the basis of numerical solution to the Maxwell-Bloch equations within an one-dimensional two-level model of a superradiant laser with a symmetric cavity where a photon lifetime is less than an incoherent relaxation time of the optical dipole oscillations of active centers, we find that a spontaneous asymmetric generation of the counter-propagating waves is possible under a continuous homogeneous pumping of an active medium. We show that such a phenomenon of a symmetry breaking of the spatial profiles of the counter-propagating waves of an electromagnetic field as well as the polarization and population inversion of an active medium in the considered case of a weak inhomogeneous broadening of an operating transition is caused by an asymmetric half-wavelength nonlinear grating of the population inversion of the transition’s energy levels which is produced by these waves.

Based on the numerical solution to the nonlinear Maxwell-Bloch equations, the joint implementation of active (parametric) and passive (coherent) mode locking for a class C heterolaser with a low-Q combined Fabry-Perot cavity in the presence of an effective distributed feedback of counter-propagating waves is demonstrated. It is shown that the multiplicity of the spectral width of the photonic band gap of the cavity to the intermode spacing far from this zone contributes to the effective phasing of quasi-monochromatic quasi-equidistant modes, thus making it possible a phenomenon of parametric coherent self-mode-locking. A number of examples are used to demonstrate typical properties of a quasi-periodic sequence of soliton-like pulses generated in the found regime, which does not require external modulation of the pump or laser parameters, or the placement of a fast-saturating absorber in it.