Optical fiber cable with large number of ribbon units containing optical fibers and enclosed in tubes

Abstract From the Canadian patent

A plurality of optical fiber ribbons, each containing a plurality of optical fibers, are loosely enclosed in a substantially fluid impervious tube of plastic material. A plurality of such ribbon enclosing tubes are wound in S or Z fashion around a central structural member which can be covered with a plastic material. The so-wound tubes are encircled by threads or tape to hold them in place, and a covering of helically wound yarns is applied around the tubes to provide strength. A plastic sheath is applied over the yarns and if, desired the sheath is covered with other layers. Any otherwise empty spaces within the tubes and between the sheath and the tubes is filled with a water blocking …