Abstract: Stabilizing an electromagnetic radiation (1) of an optical oscillator (3), in particular of a laser (13), includes measuring a deviation (35, 37, 43) between the electromagnetic radiation (1) of the optical oscillator (3) and a reference (21, 23, 39, 41) and generating a first deviation signal (35, 37, 43), controlling a first controller (55) with the first deviation signal (35, 37, 43), setting the first deviation signal (35, 37, 43, 38) by controlling at least a first manipulated variable (5, 7, 89) of at least two manipulated variables (5, 7, 89), the first manipulated variable (5, 7, 89) being controlled by a first output signal (57) of the first controller (55) and the first manipulated variable (5, 7, 89) affecting the first electromagnetic radiation (1) of the optical oscillator (3), and generating a modulation signal (65) with a modulation unit (63), and controlling the first or a second manipulated variable (5, 7, 89) with the modulation signal (65), demodulating the first output signal (57) of the f