Single-Mode Optical-Fiber Cable

Single-mode optical-fiber cable is commonly used as backbone cabling outside the building and is also usually the cable type for long-distance phone systems. Light travels through single-mode fiber-optic cable using only a single mode, meaning it travels straight down the fiber and does not "bounce" off the cable walls. Because only a single mode of light travels through the cable, single-mode fiber-optic cable supports higher bandwidth and longer distances than multimode fiber-optic cable. Devices that use single-mode fiber-optic cable typically use lasers to generate the light that travels through the cable. Since the core size of single-mode cable is much smaller than multimode fiber, the connecting hardware and especially the lasers are much more expensive than those used for multimode fiber. As a result, single-mode based systems (cable plus electronics) are more costly than multimode systems.

ANSI/TIA-568-C.3 recognizes OSI and OS2 single-mode optical fiber cables.

Optical Fiber and Telecommunications Rooms

The ANSI/TIA-568-C standard specifies that certain features of telecommunications must be adhered to in order for the installation to be specifications-compliant:

• The telecommunications outlet(s) must have the ability to terminate a minimum of two fibers into 568SC couplings.
• To prevent damage to the fiber, the telecommunications outlet(s) must provide a means of securing fiber and maintaining a minimum bend radius of 30 millimeters.
• The telecommunications outlet(s) must be able to store at least one meter of two-fiber (duplex) cable.
• The telecommunications outlet(s) supporting fiber cable must be a surface-mount box that attaches on top of a standard 4″ × 4″ electrical box.