Abstract: The present invention concerns an optical fiber cable containing a plurality of optical fibers split up into modules, each module being covered with a supporting sheath in contact with the outer optical fibers of the module so as to hold the optical fibers contained in said module tightly so that they are mechanically coupled to one another, the entire set of modules being disposed inside a covering made of an insulating material, which covering is in contact with the outer modules of the set of modules so as to form a compact assembly comprising all of the modules;wherein each optical fiber has a cut-off wavelength of not more than 1,350 nm, and, at a wavelength in the vicinity of 1,550 nm, has a mode field diameter lying in the range 7 .mu.m to 9 .mu.m, and wherein each optical fiber is provided with a substantially hermetic coating on its optical cladding.

Abstract: The present invention relates to an optical fiber cable, in particular for a distribution network, and comprising an assembly of optical fibers, wherein each of the optical fibers has a mode field diameter lying in the range 7 .mu.m to 9 .mu.m at around 1550 nm, and a cutoff wavelength less than or equal to 1.35 .mu.m, and wherein the optical fibers are assembled together in the cable by being twisted around one another or around a reinforcing element, or by being disposed lengthwise.

Abstract: The present invention relates to an optical fiber comprising an optical core surrounded by optical cladding, said optical cladding being surrounded by a substantially hermetic coating, wherein said optical fiber has a mode field diameter lying in the range 7 .mu.m to 9 .mu.m at around 1550 nm, and a cutoff wavelength that is less than or equal to 1.35 .mu.m.

Abstract: Device for sealing a container and process for detecting an attempted break-in with the aid device. In per se known manner, part of the fibres at one end of an optical fibre cable is masked and the other end of the cable is observed on illuminating the first end. According to the invention, the two cable ends are held in a seal, while masking is obtained either with the aid of a masking disk, or with the aid of a high-energy beam, which destroys the end of certain fibres. The second end of the cable is observed either with the aid of a camera, or with the aid of a sighting camera making it possible to mark the coordinates of the unilluminated fibres.