Abstract: Laser machining system (60) comprises a high-power laser (61) for generating a high-power pump laser beam (HP-MM), control signal laser (62) for generating a control signal laser beam (SS), an optical fibre (64) leading from the two lasers to a laser machining head (63). The optical fibre has an SRS amplifier fibre (65) with an inner fibre core (65a) of higher brilliance and with an outer fibre core (65b) of lower brilliance surrounding the inner fibre core. The control signal laser beam (SS) is coupled into the inner fibre core and the pump laser beam (HP-MM) is coupled into the outer fibre core. The radiation component converted from the outer fibre core into the inner fibre core due to the SRS amplification is adjusted by means of the coupled-in power of the control signal laser beam (SS) to adjust the brilliance of the machining laser beam leaving the SRS amplifier fibre.