Fiber Optic Communications
Uploaded by vanita on Jul 22, 2006
Fiber optics technology is among fastest – growing communications technologies in the world. It is increasingly being used for communications signaling, and electrical control instead of older –technology hardwired system.
Fiber optic cable uses light to transmit signals. The core of Fiber optic cable is composed of one or more thin strands of either very pure glass or plastic, millions of which can be bundled together in a sheathing.
In 1860, Alexander Graham Bell demonstrated that light reflected off of mirrors was modulated by waves of sound. Later, American researchers were able to demonstrate the transmission of an image through a bundle of glass fibers. Researchers began experimenting with cladding which greatly improved transmission characteristics by reducing the dispersion of light. Later, lasers were implemented as light sources because they could provide parallel light in a steady stream at only one wavelength.
The first of the low-loss optical fibers was created in 1970. In 1980, the first major Fiber Optic communication link between Boston, Mass, and Richmond, VA, was created. A year later, low-loss, single-mode fibers with high bandwidth and low loss capabilities to increase data transmission rates were created. Starting in the mid-eighties, the major communication companies began installing long-distance Fiber Optic communication systems using single-mode fibers. In 1988 the first transatlantic Fiber Optic cable was installed.
Since then, Optical Fiber technology has been implemented in major communication networks that have realized its significance and importance.
Two basic optical fiber are commonly being installed: singlemode and multimode. Each type has a particular use in the communication industry, although there may be some overlap in usage.
A singlemode optical cable may have a core diameter of 8 to 10 microns, while a multimode cable may have a core diameter of between 50 and 1,000 microns. A singlemode cable allows a higher bandwidth to be transmitted over a larger distance than a multimode cable.
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