DWDM or CWDM – when which technology?

Again and again we are asked when CWDM and when DWDM is used. Here is a simple explanation of the complicated abbreviations.

The application defines the choice of hardware

As always, the application decides whether DWDM (Dense Wavelength Division Multiplexing) or CWDM (Coarse Wavelength Division Multiplexing) is used.

The abbreviation “WDM” that appears in both abbreviations stands for Wavelength Division Multiplexing and describes a technology that increases the capacity of optical fibers. It increases the bandwidth by allowing different data streams to be sent simultaneously over a single fiber optic network.

Thanks to wavelength multiplexers, many different services can be bundled on one fiber and transmitted using different frequencies. The wavelength multiplexer is responsible for bundling the individual light wavelengths, the demultiplexer unbundle again. Transmission is possible in both directions.

Depending on the application, either DWDM or CWDM is used. While CWDM is the more cost-effective alternative, which is particularly suitable for first-time projects, DWDM is the powerhouse that transmits tens of times the wavelengths over a fiber pair.

Advantages of CWDM:

  • Low cost
  • More robust hardware, because less temperature sensitive
  • Suitable for initial purchase

Disadvantages of CWDM:

  • Fewer parallel services, as wider channels
  • Lower bandwidth: only up to 16 Gbit/s per channel
  • Cannot be amplified

Advantages of DWDM:

  • 80 wavelengths
  • Automatic channel switching
  • High bandwidth: up to 400 Gbit/s per channel
  • Longer distances
  • Larger networks

Disadvantages of DWDM:

  • Capital intensive
  • More complex network design requires higher expertise

So, both technologies have their right to exist! Together with our customers we evaluate the hardware that best fits the network requirements.

Active vs. passive components

Both technologies can in turn be divided into active and passive variants. As expected, the word “active” stands for the intelligence of the individual components in a WDM network. The advantage? By using the active component, every point in the network can be monitored.

We are xWDM specialists: We offer hardware components for all WDM systems. Talk to us about your challenge!

Learn about the advantages

Intelligent & secure

Active WDM

Affordable & easy

Passive WDM