Wdm In Optical Network

24 July 2017


What is WDM ?

A technology used to transmit multiple optical signals by multiplexing into an one signal. It is commonly described frequency division multiplexing while it is used in RF radio carriers.

  • In Dense Wavelength Division Multiplexing, Only 1550 nm Wavelength band is used.
  • C band (1525 - 1565 nm) and L band (1570 - 1610 nm), These bands works well with the EDFAs.
WDM Components :

  1. Transponder
  2. Muxponder
  3. Mux/Demux
  4. OADM
  5. ROADM
  6. Supervisory, DCF, VOA, Amplifiers.
  7. OLP
  8. Transponder cum OLP
  9. Muxponder cum OLP
  10. Regenerator.

The Relation between Transponder, Muxponder, Mux/Demux



It lies between the two MDXs to provide power to increase the travel distance of optical signals.

WDM - NE Types:

  1. Terminal.
  2. Dual-Terminal.
  3. ILA/OLA (Inline/Optical Line Amplifier)
  4. OADM
  5. ROADM

OADM means the Optical Add and Drop Multiplexing which is used in optical link. The major parts are,

  1. FBG - Fiber Bragg Grating
  2. Circulators. These are used for this optical operation.




  • TPDR Algorithm - Tunable-Parameter Deflection Routing Algorithm
  • OLP - Optical Line Protection.
  • FMS - Fiber Management System.
  • OSC - Optical Supervisory Channel.
  • DSF - Dispersion Compensating Fiber.
  • OADM - Optical Add and Drop Multiplexing.
  • ROADM - Reconfigurable OADM.
What is the need of OEQ ?

Optical Equalizer is used to maintain a standard power on the link where independent wavelengths are passed between two ROADM.

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