Optical modules and a method of precisely assembling the modules are provided. The method includes the step of providing a set of optical components including a plurality of beam shaping components for converting at least one initial shape in cross section of a laser beam to at least one desired shape in cross section and an optical mount for supporting the set of optical components. The method further includes holding and locating the optical mount relative to a reference axis. The method still further includes holding the optical components in position relative to the optical mount during the step of holding and locating wherein the positions of the beam shaping components are initial positions. The method includes directing a laser beam having the at least one initial shape at the set of optical components during the step of holding the optical components. The method further includes adjusting the initial positions of the beam shaping components to obtain final positions of the beam shaping components relative to the optical mount during the step of directing until the laser beam has the at least one desired shape.