SINGLE-MODE FIBER has a narrow core (eight microns or less), and the index of refraction between the core and the cladding changes less than it does for multimode fibers. Light thus travels parallel to the axis, creating little pulse dispersion. Telephone and cable television networks install millions of kilometers of this fiber every year.
Two Basic cable designs are loose-tube cable, used in the majority of outside plant installations in North America and tight-buffered cable, primarily used inside the buildings.
The modular design of loose-tube cables typically holds up to 12 fibers per buffer tube with a maximum per cable fiber count of more than 200 fibers. Loose-tube cables can be all dielectric or optionally armored. The modular buffer tube design permits easy drop-off of groups of fibers at intermediate points, without interfering with other protected buffer tubes being routed to other locations. The loose-tube design also helps in the identification and administration of fibers in the system.
Single fiber tight-buffered cables are used as pigtails, patch-cords and jumpers to terminate loose-tube cables directly into opto-electronic transmitters, receivers and other active and passive components
Multi-fiber tight buffered cables are also available and used primarily for alternative routing and handling flexibility and ease within buildings.
November 11, 2011