This blog ETU-LINK will show you how to identify the wavelength of CWDM optical module through the color of the pull ring. We all know that CWDM has a total of 12 wavelengths, with a full band range of 1270-1610nm, with each wavelength interval of 20nm. The industry divides the entire band into front wave and back wave, with the front wave band of 1270-1450nm and the back wave band of 1470-1610nm. Generally, the back wave band is chosen for ultra long distance transmission.

For a conventional optical module, we can easily judge the wavelength of the optical module from the color of the latch ring. For example, the black pull ring represents 850nm, and the blue pull ring represents 1310nm. For SFP CWDM optical module, what wavelength does the color of its pull ring correspond to? Please take a look at the table below.

Front wave (SFP CWDM special wavelength):

Backwave (SFP CWDM conventional wavelength):

Through the above table, we believe that you can clearly identify the wavelength represented by the color of the latch ring of the SFP CWDM optical module. Understanding the wavelength represented by the color of the pull ring will help us identify the module with the corresponding wavelength. The above is the product knowledge related to the SFP CWDM optical module introduced by ETU-LINK. If you want to know more about the optical transceiver, you can read the previous articles.