Fiber optic cable is a very thin glass strand through which a pulse of light is transmitted. It can transport optical signals for significant distances, whether in local area, wide area, or in metropolitan area. This article will tell some information about fiber optic cable and aim at providing a guideline on choosing the right fiber optic cable.
Fiber optic cable can be divided into single-mode fiber cable and multimode fiber cable. Single-mode optical fiber generally has a core diameter of 9 µm and requires laser technology for sending and receiving data. It can carry a signal for miles, which makes it ideal for telephone and cable television providers. As the name suggests, multimode fiber permits the signal to travel in multiple modes, or pathways, along the inside of the glass strand or core. It is available with fiber core diameters of 62.5 µm or 50 µm. Although the core sizes of single-mode fiber and multimode fiber differ, both fiber types end up with an outer diameter of about 250 µm.
The major difference between indoor and outdoor fiber optic cable is water blocking. Any conduit is someday likely to get moisture in it. Outdoor cables are designed to protect the fibers from years of exposure to moisture. Indoor cables are what we call “tight-buffered” cables, where the glass fiber has a primary coating and secondary buffer coatings that enlarge each fiber to 900 microns—about 1mm or 1/25-inch, to make fiber easier to work with.
Fiber optic cable jackets can provide strength, integrity and overall protection of the fiber member. PVC is widely used as a cable jacket for many applications—computers, communications, low-voltage wiring, etc. PVC can potentially be dangerous in a fire situation, releasing heavy smoke and hydrogen chloride gas, which can be irritating to humans and corrosive to electronic devices. OFNP, or plenum jackets, are suitable for use in plenum environments such as drop-ceilings or raised floors. Many data centers and server rooms have requirements for plenum-rated cables. LSZH is a jacket made from special compounds which give off very little smoke and no toxic halogenic compounds when burned.