Module 19 : WDM Components
Lecture     : WDM Components - II
  network supported only a few wavelengths at low bit rates over a single fiber. Because of insertion loss and signal degradation, OADMs were not added in the circuit. These days, however, a point to point network can be used over very long hauls (thousands of kilometers) with many components, including amplifiers, wavelength converters, OXCs etc.
   
 

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Ring topology , modeled after the Fiber Distributed Data Interface (FDDI) used in early optical networks which consisted of two rings (called the primary and the secondary rings) running in opposite directions with the nodes placed along the circular paths. In case of a fault at any of the nodes, it was automatically passed by the adjacent node by optically connecting the primary and the secondary rings. SONET rings with nodes having OADMs are quite popular.

\includegraphics{wdm19}
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