Differences Between CWDM and DWDM

Channel Spacing

There is a significant difference between CWDM and DWDM in their channel spacing.The standard channel spacing of CWDM is 20nm, while the channel spacing of DWDM is 1.6/ 0.8/ 0.4nm(200GHz/ 100GHz/ 50GHz grid). Therefore, CWDM has a wider spacing than DWDM.

Transmission Distance

DWDM wavelengths are highly integrated with the fiber during transmission, so DWDM is able to reach a longer distance than CWDM. The maximum reach of CWDM is about 120km, but DWDM system can go much further with full use of bandwidth resources.

Cost

The temperature tuning is very difficult to realize because the temperature distribution is nonuniform in a wide wavelength range. As a result, the use of cooling laser technique increases the cost of DWDM system. While CWDM system doesn't need the cooling laser technique, thus significantly reducing cost.

Summary

In a word, there are three main differences between CWDM and DWDM: channel spacing, transmission distance and cost. How to choose these two products should be based on different characteristics and practical application.
Vsunlight can offer CWDM with wavelength of 1271-1611nm, channels of 4CH/8CH/18CH, and different packaging. DWDM with the wavelength of C20-C62(0.4nm or 0.8nm spacing) are provided by Vsunlight.