Method for controlling the propagation of water in an optical cable

A method for controlling the spread of water in an optical cable (100) for communication comprising: - a retaining element (2); - at least two individual optical fibers (3) housed within said retaining element (2); and - one water swellable yarn (4) housed within said retaining element (2) and disposed adjacent and in contact with said at least two individual optical fibers (3); wherein the method comprises selecting the minimum volume of water swellable yarn (4) according to the following equation: where Vw is the minimum volume of water swellable yarn (4) after swelling upon contact with water; VTF is the total free volume in the holding element (2); k is a constant> = 180 mm3 / m; R is a constant> = 1.4; and Vt is the free volume for each individual optical fiber (3).