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What is the difference between CWDM and DWDM multiplexer?
Knowledge Base + 2024.01.08

CWDM (Coarse Wavelength Division Multiplexing) and DWDM (Dense Wavelength Division Multiplexing) are both technologies used in fiber optic communication systems to increase the capacity of the network by multiplexing multiple optical signals onto a single fiber. The main difference between the two lies in the spacing between the wavelengths used.

CWDM typically multiplexes a small number of wavelengths (typically 8-18) with wider spacing between wavelengths (typically 20nm apart). This allows for easier and cheaper components and is better suited for shorter distance and lower capacity applications.

DWDM, on the other hand, can multiplex a much larger number of wavelengths (typically 40-160) with much tighter spacing between wavelengths (typically 0.8nm -1.6nm apart). This allows for much higher capacities and longer distance transmission, but also requires more precise and expensive components.

In summary, CWDM is typically used for shorter distance and lower capacity applications, while DWDM is used for longer distance and higher capacity applications.

CWDM vs DWDM: Advantages and Disadvantages

As mentioned above, the primary difference between DWDM and CWDM is the channel spacing (CWDM has almost 100 times wider channel spacing). This makes CWDM a simpler technology, resulting in advantages and disadvantages of the different systems with regard to cost, performance, and so on.

CWDM Advantages and Disadvantages

CWDM AdvantagesCWDM Disadvantages
  • Lower power consumption

  • Smaller space requirements

  • Can use SMF fiber or MMF cable

  • Can use LED’s or Laser’s for power

  • Larger individual payloads per channel

  • Smaller and cheaper wave filters

  • Cost savings on start-up and expansion

  • Less capacity than DWDM

  • Less range

  • Regeneration vs amplification

  • O, A and M functions are not carrier-class

DWDM Advantages and Disadvantages

DWDM AdvantagesDWDM Disadvantages
  • Maximum capacity system available

  • Maximum distance capability with EDFA’s

  • Repeater “amp” sites can be reduced

  • Pay as you grow expansion

  • Mature O, A and M systems are developed

  • Need more space

  • Need more power

  • Need high accuracy lasers and wave filters

  • Expensive EDFA’s for amplifiers

  • Start-up costs are more than the equivalent CWDM system