The invention relates to a Method for operating a frequency agile tunable self-injection locking laser system being formed by a laser device coupled to at least one optical resonator, wherein a diode current of a laser diode of the laser device is controllable and wherein the optical resonator is controllable by controlling a piezo or an electro-optical actuator configured to apply a variation of the refractive index of the resonator material through mechanical stress or an electric displacement field, respectively, at least partially onto the at least one optical resonator depending on an actuation voltage, inducing a change in the effective optical path length of the at least one optical resonator, comprising the steps of: - Selecting a self-injection locking range among a plurality of self-injection locking ranges by varying a laser diode current and monitoring self-injection locking ranges, wherein self-injection locking ranges corresponding to current ranges in which self-injection locking occurs, wherein the self-injection locking corresponds to an optical feedback phase for back-reflected light from the optical resonator into the laser device, - setting the diode current from the current range of the selected self-injection locking mode; - determining a maximum tuning range of the actuation voltage in which self-injection locking is maintained; - operating the laser system with actuation voltages in a range depending on the determined tuning range.