In at least one embodiment of the wavelength-tunable light source, it comprises an output source, which is capable in operation of generating electromagnetic radiation. Furthermore, the light source has a wavelength-selective first filter element, which is situated downstream from the output source. Moreover, the light source contains a first amplifier medium, which is situated downstream from the first filter element and is capable of at least partial amplification of the radiation emitted by the output source. The light source further comprises at least one wavelength-selective second filter element, which is situated downstream from the first amplifier medium, the second filter element having an optical spacing to the first filter element. The first filter element and the at least one second filter element are tunable via a control unit, which the light source has.