Abstract: The invention relates to a method of producing an optical cable (1) or a modular unit for an optical cable. According to the inventive method, a metal strip that is drawn off a supply reel is gradually shaped to an open seam tube. At least one optical waveguide (2) is drawn off a second supply reel and introduced into the open seam tube. The longitudinal seam of the open seam tube is closed by welding and after welding an excessive length of the optical waveguide vis-á-vis the metal tube is produced in said metal tube. The welded metal tube (3) is crimped, dented or undulated (3b) to produce.