Friday, August 23, 2013

Optical TDM Advantages & Disadvantages

OTM was introduced because TDM Time Division Multiplexing couldn't be use for Optical Links

OPTICAL TDM NETWORKS

  • OTDM requires the use of very short optical pulse because these network operates at a rate of 100 Gbps & above
  • At such high rates transmission properties of the optical fiber interact with optical signal
  • In particular , dispersion has a great impact on distance bandwidth product OR BL product
DRAWBACKS OF OTDM

  • OTDM is synchronization dependent
  • To maintain synchronization at rate of 100 Gbps & above is challenging
  • Lack of synchronization may result in collision on the channel
  • TDM frame structure dictates the transmissions & reception of client traffic & thereby destroy the transparency against different protocol
  • Protocol transparency is a problem in OTDM network
Three types of networks

      1.Transparent DWM Network

A network which doesn't require any OEO Optical-Electric-Optical conversion

      2.OPAQUE DWM Network

A network which completely blocks a signal

      3.Translucent DWM Network 

 A network which doesn't block the signal, signal is sent using optical bypass

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