Spectrum collapse, narrow lines, and soliton combs with multi-frequency laser diodes locked to optical microresonators

We introduce a technique capable to produce and control stabilized single-frequency emission with a sub-kHz linewidth and independently soliton comb generation from a multi-frequency regular Fabry-Perot laser diode self-injection locked to a high-Q optical microresonator. We also observed novel regimes of controllable single, dual, and multiple-frequency generation that may be useful for the creation of narrow-linewidth lasers required for the spectroscopy, LIDARs, and telecommunications. For analysis of the considered effects original theoretical models taking into account self-injection locking effect, mode competition and Bogatov asymmetric mode interaction were developed and numerical modeling was performed.