A frequency agile tunable self-injection locking laser system being formed by a laser device coupled to at least one optical resonator and method and controller therefor are disclosed. A diode current and an optical resonator are controllable. A self-injection locking range is selected and the self-injection locking range corresponds an optical feedback phase for back-reflected light from the optical resonator into the laser device. A diode current is set and a maximum tuning range of the actuation voltage in which self-injection locking is maintained is determined. The laser system is operated with actuation voltages in a range depending on the determined tuning range.