Why fiber optics?

Fiber optics is nothing new to the world of networking. What is new are the ways in which fiber is being used to provide services and revenue for all of the customers who use it. The limit on how much bandwidth or data can be carried across a copper line can become a bottleneck for enterprise access and revenue. The bottleneck oftentimes appears in the metropolitan area network. Low bandwidth access speeds and/or very expensive high bandwidth speeds present problems for individual users and enterprise customers alike. Limited to T1 speeds (1.544 Mbps) or T1 multiples like T3, most enterprise customers and individuals are languishing in the success of e-commerce and on-line access. With the current technologies employed in the metropolitan networks today, additional bandwidth is expensive, if available at all. Optical fiber offers bandwidth—lots of it.
Combined with technologies like Wavelength Division Multiplexing (WDM), bandwidth availability can grow exponentially with optical fiber. With the potential to exponentially grow bandwidth and thereby revenue, optical fiber is worth learning a bit about.

Multimode and Single-mode fiber

There are two basic types of fiber: Multimode and Single Mode.

Multimode fiber has a larger core and therefore supports multiple light wave paths. Multimode fiber was the first type of fiber used for data networks and is usually abbreviated with the letters MMF. There are two diameters used with multimode fiber—62.5 micron and 50 micron. Both types have a 125-micron cladding. Multimode fiber is used for distances of typically less than 2 km because, with the support of multiple paths or modes, there is a greater chance that some light traveling down a certain path will arrive later than light traveling directly down the center of the core, causing the remote end to see fading in the light signal.

Multimode Fiber Applications

LAN (FDDI, ATM, 10baseF- short haul.)
Office Networks
Sensors
Short distance at moderate speeds

Single-mode fiber (SMF) has a core that supports one path or mode by which light may travel. The core of an SMF is much smaller than the core of an MMF—8.3 or 7.1 microns versus 62.5 or 50 nm. 125 micron cladding surrounds both SMF cores. Lasers are the required light source for SMF, which means that although the cost of SMF is frequently less than that of MMF, the cost of the light source (laser) makes SMF installations cost-prohibitive for short distances.
However, single-mode fiber can send high bit rate signals over long distances—beyond 2 km.

Duplex Single Mode Fiber Optic Cable Assemblies

FC to ST Single Mode Fiber Optic Cable, 8.3/125 Duplex PVC ZIPCORD
SC to SC Single Mode Fiber Optic Cable, 8.3/125 Duplex PVC ZIPCORD
SC to ST Single Mode Fiber Optic Cable, 8.3/125 Duplex PVC ZIPCORD
ST to ST Single Mode Fiber Optic Cable, 8.3/125 Duplex PVC ZIPCORD

Simplex Single Mode Fiber Optic Cable Assemblies

ST to ST Single Mode Fiber Optic Cable, 8.3/125 SIMPLEX PVC ZIPCORD
SC to SC Single Mode Fiber Optic Cable,  8.3/125 SIMPLEX 3.0MM, PVC

Single-mode Fiber Applications