At present, WDM (Wavelength Division Multiplexing) technology is developing very rapidly, and has shown great vitality and bright development prospects. In the same optical fiber, two or
more optical wavelength signals are transmitted through different optical channels at the same time, which is called optical wavelength division multiplexing technology, or WDM for short.
Optical wavelength division multiplexing includes CWDM and DWDM.
Next, I will introduce the difference between CWDM and DWDM optical modules.
Different wavelength intervals
The spacing between CWDM carrier channels is relatively wide, and the interval between each band is 20nm. Therefore, only about 8 to 16 wavelengths can be multiplexed on the same
optical fiber, while the spacing between DWDM carrier channels is relatively narrow, with intervals of 0.2nm, 0.4nm, and 0.8nm for each band. , 1.6nm, can multiplex 80 to 160
wavelengths, the difference between “sparse” and “dense” comes from this.
The wavelength range is different
The working wavelength range of CWDM is between 1270nm-1610nm, while the working wavelength of DWDM is a part selected in CWDM, there are two bands of 1525nm-1565nm (C band)
and 1570nm-1610nm (L band).
Device cost is different
CWDM modulates lasers using uncooled lasers, while DWDM uses cooled lasers. Cooled lasers are temperature tuned, uncooled lasers are electronically tuned. Since the temperature
distribution in wavelength range is very uneven, it is very difficult to implement temperature tuning, and the cost is also high. Therefore, the cost of DWDM is much higher than that of
CWDMtechnology.
Application difference
DWDM optical modules can complete the transmission tasks of long-distance and large-capacity long-distance trunk networks. Some large-capacity metropolitan area network core nodes,
telecom 5G, metropolitan area networks, backbone networks, and some data centers will also be applied to DWDM optical modules and equipment. . Compared with DWDM, the cost of
CWDM will be much lower, and it is mainly used in the access layer of the metropolitan area network, enterprise network, campus network, etc. CWDM optical modules are widely used,
which greatly saves the cost of upgrading the network for users.
Different wavelength division multiplexers/demultiplexers
CWDM optical modules need to be used with CWDM wavelength division multiplexers and CWDM demultiplexers to achieve transmission, while DWDM optical modules need to be used
with DWDM wavelength division multiplexers and DWDM demultiplexers.
I hope my explanation can help you better understand WDM technology.
If you have more ideas to share, please contact csd@telecomte.com. thanks.
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