What is the difference between CWDM and DWDM optical modules?

CWDM and DWDM are two of the most popular WDM technologies used by telecoms and are mainly used in WDM / demultiplexers. WDM / demultiplexers are used in conjunction with WDM optical modules, so let's take a look at the differences between CWDM and DWDM optical modules.

I. Different bands

1. CWDM optical modules are available in the wavelength range of 1270-1610nm, with a band interval of 20nm, with a total of 18 channels to choose from. The CWDM optical modules are available in 155M, 1.25G and 10G transmission rates, corresponding to SFP, SFP+/XFP package types.

2, DWDM optical module wavelength is located in C-band (C17-C61), the range between 1563.86-1528.77nm, band interval 0.8nm, a total of 45 channels can be selected, the common transmission distance is 40KM, 80KM. 10G DWDM optical module package types are SFP+, XFP two.

II. different application scenarios

1. CWDM optical modules are used in metro access networks, enterprise networks and campus networks.

2、DWDM optical modules are used in long-haul trunk networks and core nodes of high-capacity metropolitan networks.

III. Different WDM / demultiplexer used

1. CWDM optical modules need to be used with CWDM wavelength division multiplexers and CWDM demultiplexers to achieve optical network interconnection.

2. DWDM optical modules need to be used with DWDM wavelength division multiplexers and DWDM demultiplexers to achieve optical network interconnection.

IV. CWDM/DWDM optical modules use different lasers

DWDM optical modules are used with cooled lasers (temperature coordinated) in order to prevent wavelength drift outside the filter channels of the multiplexer and demultiplexer due to temperature changes, while CWDM optical modules are used with uncooled lasers (electronically coordinated).

V. Different costs

For the same transmission distance, the DWDM optical modules DWDM optical modules are more expensive than CWDM optical modules due to the fact that modulated lasers are more expensive than CWDM optical modules.

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