Coarse wavelength division multiplexing (CWDM) and dense wavelength division multiplexing (DWDM) are used for increasing the bandwidth of fiber by combining optical signals of different wavelengths on one strand of fiber. This article will discuss the differences between CWDM and DWDM.

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Coarse wavelength division multiplexing (CWDM) and dense wavelength division multiplexing
(DWDM) are used for increasing the bandwidth of fiber by combining optical signals of different
wavelengths on one strand of fiber. This article will discuss the differences between CWDM and DWDM.
CWDM and DWDM are both effective solutions to solve the increasing bandwidth capacity of
information transmission. But they differ from each other in many aspects. The below parts will
discuss some differences between CWDM and DWDM.
Channel Spacing

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The channel spacing is the nominal difference in frequency or wavelength between two adjacent
optical channels. CWDM has a wider channel spacing than DWDM. CWDM can transport 18
wavelengths with a channel spacing of 20nm in the spectrum grid from 1470 nm to 1610 nm.
On the other hand, DWDM can carry 40, 80, 96, or up to 160 wavelengths with a narrower spacing
of 0.8/0.4nm (100 GHz/50 GHz grid). Its wavelengths are from 1525nm to 1565nm (C band) and
1570nm to 1610nm (L band).
Transmission Distance
DWDM can have a long-range transmission distance by keeping the wavelength highly integrated.
The amplified wavelengths can make DWDM suffer less interference over a larger run of cable.
CWDM has a short-range transmission distance. Usually, CWDM can transmit data up to 160 km.
Modulation Laser
The CWDM uses the uncooled laser, while the DWDM uses the cooling laser. Cooling laser adopts
temperature tuning, which ensures better performance, higher safety, and a longer lifespan of the
DWDM. In addition, a DWDM consumes more power consumption than a CWDM.

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Cost
Generally, the cost of DWDM is four or five times higher than CWDM. The higher cost of DWDM
mainly contributes to the cooling laser technique, which can realize temperature tuning.
Conclusion
CWDM provides low power consumption, low capacity, and low cost than DWDM. However,
DWDM provides high capacity and better performance than CWDM when transmitting a greater
number of multiple wavelengths on a singer fiber. Sun Telecom specializes in providing one-stop
total fiber optic solutions for all fiber optic application industries worldwide. Contact us if any
needs.