Coherent mode interaction and multiple combs in the spectrum of a superradiant laser

For a laser with large inhomogeneous and small homogeneous broadening of the spectral line of the active medium, a new method is proposed for obtaining multiple combs in the lasing spectrum, which are due to self-locking of a large number of modes at the wings of the spectrum and the emission of a periodic sequence of pulse trains by two superradiant modes at its centre. The method does not require any additional elements or external influences on the laser and is based on the predicted phenomenon of double resonance, which is realised in a wide range of parameters when using a low-Q Fabry–Perot distributed-feedback cavity and includes: 1) parametric resonance, i.e. the frequency difference between two superradiant modes is twice the intermode interval on the wings of the spectrum, and 2) time resonance, i.e. the repetition period of trains of the superradiant mode pulses is a multiple of the time it takes a soliton-like pulse, formed by the self-locked modes, to travel around the cavity.