• Definition
• Fiber Optic vs. copper
• Fiber Construction
• Features
• Advantage and Disadvantage of Optical Fiber
• Discussion / Opinion

Definition

A high-bandwidth transmission medium that carries data signals in the form of pulses or light. It consists of a thin cylinder of glass or plastic, called the core, surrounded by a concentric layer of glass or plastic called the cladding.

Fiber Construction

Cable Composition

• Composition of a typical fiber-optic cable. A core is surrounded by cladding, forming the fiber. In most cases, the fiber is covered by a buffer layer that protects it from moisture. Finally, the entire cable is encased in an outer jacket.

• Both core and cladding can be made of either glass or plastic but must be of different densities. In addition, the inner core must be ultrapure and completely regular in size and shape. chemical differences in material, and even small variations in the size or shape of the channel, alter the angle of reflection and distort the signal. Some applications can handle a certain amount of distortion and their cables can be made more cheaply, but others depend on complete uniformity.

• The outer jacket (or sheath) can be made of several materials, including Teflon coating, plastic coating, fibrous plastic, metal tubing, and metal mesh. Each of these jacketing materials has its own purpose. Plastics are lightweight and inexpensive but do not provide structural strength and can emit fumes when burned. Metal tubing provides strength but raises cost. Teflon is lightweight and can be used in open air, but it is expensive and does not increase cable strength. The choice of the material depends on where the cable is to be installed.

Fiber-Optic Connectors

Connectors for fiber-optic cable must be as precise as the cable itself. With metallic media, connections are not required to be exact as long as both conductors are in physical contact With optical fiber, on the other hand, any misalignment of one segment of core either with another segment or with a photodiode results in the signal reflecting back to ward the sender, and any difference in the size of two connected channels results in a change in the angle of the signal. In addition, the connection must be complete yet not overly tight. A gap between two core results in a dissipated signal; an overly tight connection can compress the two cores and alter the angle of reflection.

Features

Single-Mode – Single Path for all light
Wave Length – 1310 nm / 1550 nm

Multi-Mode – Multitude of path for all light
Wave Length – 850 nm

Advantage of Optical Fiber

The major advantages offered by fiber-optic cable over twisted-pair and coaxial cable are noise resistance, less signal attenuation, and higher bandwidth.

• Noise resistance. Because fiber-optic transmission use light rather than electricity, noise is not a factor. External light, the only possible interference, is blocked from the channel by the outer jacket.

• less signal attenuation. Fiber-optic transmission distance is significantly greater than that of the guided media. A signal can run for miles without requiring regeneration.

• Higher bandwidth. Fiber-optic cable can support dramatically higher bandwidths (and hence data rate) than either twisted-pair or coaxial cable. Currently, data rates and bandwidth utilization over fiber-optic cable are limited not by the medium but by the signal generation and reception technology available.

Disadvantages of Optical Fiber

The main disadvantages of fiber optics are cost, installation/maintenance, and fragility.

• Cost. Fiber-optic cable is expensive. Because any impurities or imperfections in the core can throw off the signal, manufacturing must be painstakingly precise. Also, a laser light source can cost thousands of dollars, compared to hundreds of dollars for electrical signal generators.

• Installation/maintenance. Any roughness or cracking in the core of an optical cable diffuses light and alters the signal. All splices must be polished and precisely fused. All connections must be perfectly aligned and matched for core size and must provide a completely light-tight seal. metallic media connections, on the hand, can be made by cutting and cramping using relative unsophisticated tools.

• Fragility. Glass fiber is more easily broken than wire, making it less useful for applications where hardware portability is required.

As we have discussed, we thought that the fiber optic was  the best solution for overcoming today's challenges. Companies and organizations speed of transferring information from one end to the another end should be faster if fiber optic was used. But, seem that to implement this idea, companies or organizations need to spend a lot of money.And, due to the economic downturns, many of the companies had revised their plans. Only companies and organizations with strong supported financial background are able to realize it. And these companies or organizations were believed to become the market's pioneer.