An optical system for a laser processing machine, with an optical element in a plug of a fiber optic cable

An optical system (2) for laser processing machine, comprising a) a fiber optic cable (3), (with an optical fiber 5) for transmitting an injected laser beam (1, 1f) to a machining head (4), and with a plug (6) for connecting the optical fiber (5) to the machining head (4 ) b) a working head (4), having a plug receptacle (8) for receiving the plug (6), and an imaging optical system (18), the exiting (in a plug is inserted 6) a (from the optical fiber 5) laser beam (1a) in focused beam propagation direction according to the machining head (4), in particular on a surface of a workpiece (30) thereof for processing, is characterized in that in the plug (6) of the light guide (3) an optical element (13) is arranged, depicting a fiber end face (12) of the optical fiber (5) in an intermediate focus (14), that the image of the fiber end face in the intermediate focus (14) is smaller than the fiber end face (12), and the divergence of outgoing DIVZW of the intermediate focus (14) laser beam (1b) is greater than the divergence DIVFE of from the fiber end face (12) exiting the laser beam ( 1a) and that focuses on the inserted plug (6), the imaging optics (18) of the machining head (4) to the intermediate focus (14) outgoing laser beam (1b) in the beam propagation direction of the machining head (4). The invention makes it possible to image a machining head which is adapted to the fiber end face of an inserted optical cable to be able to use in connection with lasers of higher power in a simple manner.