Shitikov, Artem E.Lobanov, Valery E.Kondratiev, Nikita M.Voloshin, Andrey S.Lonshakov, Evgeny A.Bilenko, Igor A.2021-07-172021-07-172021-07-172021-06-2510.1103/PhysRevApplied.15.064066https://infoscience.epfl.ch/handle/20.500.14299/180008WOS:000670306800004We experimentally observe a self-injection locking regime of the gain-switched laser to a high-Q optical microresonator. We reveal that the comb generated by the gain-switched laser experiences a dramatic reduction of comb-teeth linewidths in this regime. We demonstrate the Lorentzian linewidth of the comb teeth of sub-kHz scale as narrow as for a nonswitched self-injection locked laser. Such a setup allows generation of high-contrast electrically tunable optical frequency combs with tunable comb-line spacing in a wide range from 10 kHz up to 10 GHz. The characteristics of the generated combs are studied for various modulation parameters & mdash;modulation frequency and amplitude, and for parameters, defining the efficiency of the self-injection locking & mdash;locking phase, coupling efficiency, and pump frequency detuning.Physics, AppliedPhysicsnarrow-linewidtharchitecturetext::journal::journal article::research article