120 likes | 267 Views
1. Introduction. Communication Links. Undersea Optical Fiber Backbones. Fiber Data Rate. Fiber Capacity. http://www.laserfocusworld.com/articles/article_display.html?id=277158. Multiplexing. TDM Standards. Standards developed for optical fiber communications rates
E N D
1. Introduction EE466 Fall 2007
Communication Links EE466 Fall 2007
Undersea Optical Fiber Backbones EE466 Fall 2007
Fiber Data Rate EE466 Fall 2007
Fiber Capacity http://www.laserfocusworld.com/articles/article_display.html?id=277158 EE466 Fall 2007
Multiplexing EE466 Fall 2007
TDM Standards • Standards developed for optical fiber communications rates • Synchronous Optical NETwork (SONET) • Synchronous Digital Hierarchy (SDH) EE466 Fall 2007
Optical Signal • Optical signals are typically sent using on-off keying (OOK) • Power received: 1 • No power: 0 • Two primary formats • Nonreturn to zero (NRZ) • Return to zero (RZ) EE466 Fall 2007
Basic Optical Communication Link • Electrical signal transferred to another location • Electrical-to-Optical (E-O) conversion • Modulated laser • Signal transmission • Optical fiber • Optical-to-Electrical (O-E) conversion • Detector EE466 Fall 2007
Signal Transmission • Signal is attenuated as it propagates through the fiber • Decrease in signal amplitude • Reduction in signal-to-noise ratio (SNR) • Pulse is spread in time • Called signal dispersion • Causes inter-symbol interference (ISI) EE466 Fall 2007
Additional Components • External modulator • Better signal—lower signal dispersion • Optical amplifier • Amplifies signal to overcome attenuation EE466 Fall 2007
Topics to be Covered • Fibers • Attenuation • Dispersion • Sources • Detectors • System performance EE466 Fall 2007