Complete Hardware Guide for EX8208 Ethernet Switches
Understanding EX8200 Switch
To determine the power budget and power margin needed for
•Signal Loss in Multimode and
•Attenuation and Dispersion in
Signal Loss in Multimode and Single-Mode Fiber-Optic Cable
Multimode fiber is large enough in diameter to allow rays of light to reflect internally (bounce off the walls of the fiber). Interfaces with multimode optics typically use LEDs as light sources. However, LEDs are not coherent light sources. They spray varying wavelengths of light into the multimode fiber, which reflects the light at different angles. Light rays travel in jagged lines through a multimode fiber, causing signal dispersion. When light traveling in the fiber core radiates into the fiber cladding (layers of lower refractive index material in close contact with a core material of higher refractive index),
For information about the maximum transmission distance and supported wavelength range for the types of
Attenuation and Dispersion in Fiber-Optic Cable
An optical data link functions correctly provided that modulated light reaching the receiver has enough power to be demodulated correctly. Attenuation is the reduction in strength of the light signal during transmission. Passive media components such as cables, cable splices, and connectors cause attenuation. Although attenuation is significantly lower for optical fiber than for other media, it still occurs in both multimode and
Dispersion is the spreading of the signal over time. The following two types of dispersion can affect signal transmission through an optical data link:
•Chromatic dispersion, which is the spreading of the signal over time caused by the different speeds of light rays.
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