Fiber Optic Wiki

Fiber Optic Communication

June 12, 2011

Optical fiber can be used as a medium for telecommunication and networking because it is flexible and can be bundled as cables. It is especially advantageous for long-distance communications, because light propagates through the fiber with little attenuation compared to electrical cables. This allows long distances to be spanned with few repeaters. Additionally, the per-channel light signals propagating in the fiber can be modulated at rates as high as 111 gigabits per second,[12] although 10 or 40 Gb/s is typical in deployed systems.[citation needed] Each fiber can carry many independent channels, each using a different wavelength of light (wavelength-division multiplexing (WDM)). The net data rate (data rate without overhead bytes) per fiber is the per-channel data rate reduced by the FEC overhead, multiplied by the number of channels (usually up to eighty in commercial dense WDM systems as of 2008[update]).

Selecting the Right Attenuator 1

June 11, 2011

An fiber optic attenuator is a device used to reduce the power level of an optical signal, either in free space or in an optical fiber. They are commonly used in fiber optic communications. The basic types of fiber optical attenuators are fixed, step-wise variable, and continuously variable. In some cases an optical light source can overload a detector to the point where it cannot distinguish between the presence or absence of light pulses. That is when an attenuator is quite handy.