Saturday, September 13, 2008

how does the optical fiber communication

Ever since ancient times, people had a principal need to communicate with one another. This need created interests in devising communication systems for sending messages from one distant place to another. Optical communication methods were of special interest among the many systems that people tried to use. One of the earliest known optical transmission links was a fire-signal method used by the Greeks in the eighth century BC for sending alarms, calls for help, or announcements of certain events. Improvements of these optical transmission systems were not pursued very actively because of technology limitations at the time. For example, the speed of sending information over the communication link was limited since the transmission rate depended on how fast the senders could move their hands, the optical signal receiver was the error-phone human eye, line-of-sight transmission paths were required, and atmospheric effects such as fog and rain made the transmission path unreliable. Thus it turned out to be faster, more efficient, and more dependable to send messages by a courier over the road network.

Subsequently, no significant advances for optical communications appeared until the invention of the laser in the early 1960s and a series of technology developments related to optical fibers around 1970. These events finally allowed practical light wave communication systems to start being fielded worldwide in 1978. These systems operate in the near-infrared region of the electromagnetic spectrum and use optical fibers as the transmission medium. The goal of this book is to describe the various technologies, implementation methodologies, and performance measurement techniques that make that make optical fiber communication systems possible. The reader can find additional information on the theory of light propagation in fibers, the design of links and networks, and the evolution of optical fibers, photonic devices, and optical fiber communication systems and conference proceedings.

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