Text says current practical limit is 10 gbsecond

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Unformatted text preview: current practical limit is 10 Gb/second, primary limited - need for electrical/optical/electrical conversion. 100 Gb/sec. has been achieved in Lab, and > 50,000 Gb/second could be achieved. Instead of frequency, light signals are described in terms of wavelengths, ë. ë = c/f, where c is the speed of light, 3*108 meters/second. Wavelength bands for optical fiber are centered at 0.85, 1.3, and 1.55 microns. In these bands, attenuation is only about 0.2 dB per kilometer. 1 micron = 10-6 meters. Thus, at 1.3 microns, f = 3*108/(1.3*10-6) = 2.31*1014 herz! A deviation of 1 gigaherz = 109 hz from this center is less than 1/100,000 of the center frequency. The bands are about 25,000-35,000 gigaherz wide. Can send thousands of kilometers, small distortion The 0.85 micron band has more attenuation, but the materials and devices are cheaper. Optical signaling is generally by onoff pulses. Optical interfaces can be passive or active. Passive: Passive Star broadcast: Light coming into junction splits about equally. With n receivers, each received power is 1/n of original. Active:...
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This document was uploaded on 04/03/2014 for the course EE 362 at Penn State.

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