A submarine optical cable having a central polymeric buffer tube, said cable being particularly suitable for long-haul repeatered systems. A longitudinal reinforcing element is embedded into the walls of the central polymeric buffer tube which is of relatively small dimensions. The presence of said reinforcing element allows a precise control over the excess fiber length within the buffer tube. This reinforcing element is of relatively small diameter, in order to comply with the requirements of reduced dimensions of the buffer tube. Notwithstanding this relatively small diameter, said longitudinal reinforcing element allows for a good control over the longitudinal shrinkage of the polymeric buffer tube within the submarine cable.