A laser welding apparatus comprising: - at least one first laser device, each first laser device connected to at least one first optical feed fiber for delivering a first laser beam; - at least one second laser device, each second laser device connected to at least one second optical feed fiber for delivering a second laser beam; - a beam combiner connected to the first optical feed fiber, to the second optical feed fiber, and to a multi-core optical fiber (35, 50), the multi-core optical fiber comprising a first core with a circular cross-section located in the center of the multi-core optical fiber and a second core with an annular cross-section spaced from and concentric to the first core, wherein the at least one first optical feed fiber is aligned with the first core of the multi-core optical fiber and the at least one second optical feed fiber is aligned between inner and outer diameters of the annular second core of the multi-core optical fiber, the first core and the second core are connectable to a laser processing head, to direct a composite laser beam comprising a first output laser beam and a second output laser beam to a workpiece to be welded, the first output laser beam has a circular cross-section and the second output laser beam has an annular shape concentric to and spaced from the first output laser beam at the workpiece, the second laser device is a fiber laser device or a fiber-coupled laser device, the apparatus is configured to form the second output laser beam at least on the basis of the second laser beam, characterized in that two laser sources are comprised in the second laser device, and the second output laser beam comprises two beams (2a, 2b) achieved by setting the two laser sources of the second laser device having a first wavelength and a second wavelength respectively, the first wavelength and the second wavelength having a difference of at least 10 nanometers. - at least one first laser device, each first laser device connected to at least one first optical feed fiber for delivering a first laser beam; - at least one second laser device, each second laser device connected to at least one second optical feed fiber for delivering a second laser beam; - a beam combiner connected to the first optical feed fiber, to the second optical feed fiber, and to a multi-core optical fiber (35, 50), the multi-core optical fiber comprising a first core with a circular cross-section located in the center of the multi-core optical fiber and a second core with an annular cross-section spaced from and concentric to the first core, wherein the at least one first optical feed fiber is aligned with the first core of the multi-core optical fiber and the at least one second optical feed fiber is aligned between inner and outer diameters of the annular second core of the multi-core optical fiber, the first core and the second core are connectable to a laser processing head, to direct a composite laser beam comprising a first output laser beam and a second output laser beam to a workpiece to be welded, the first output laser beam has a circular cross-section and the second output laser beam has an annular shape concentric to and spaced from the first output laser beam at the workpiece, the second laser device is a fiber laser device or a fiber-coupled laser device, the apparatus is configured to form the second output laser beam at least on the basis of the second laser beam, characterized in that two laser sources are comprised in the second laser device, and the second output laser beam comprises two beams (2a, 2b) achieved by setting the two laser sources of the second laser device having a first wavelength and a second wavelength respectively, the first wavelength and the second wavelength having a difference of at least 10 nanometers. the at least one first optical feed fiber is aligned with the first core of the multi-core optical fiber and the at least one second optical feed fiber is aligned between inner and outer diameters of the annular second core of the multi-core optical fiber, the first core and the second core are connectable to a laser processing head, to direct a composite laser beam comprising a first output laser beam and a second output laser beam to a workpiece to be welded, the first output laser beam has a circular cross-section and the second output laser beam has an annular shape concentric to and spaced from the first output laser beam at the workpiece, the second laser device is a fiber laser device or a fiber-coupled laser device, the apparatus is configured to form the second output laser beam at least on the basis of the second laser beam, characterized in that two laser sources are comprised in the second laser device, and the second output laser beam comprises two beams (2a, 2b) achieved by setting the two laser sources of the second laser device having a first wavelength and a second wavelength respectively, the first wavelength and the second wavelength having a difference of at least 10 nanometers.