What are the 25G SFP28 optical modules for the fronthaul of the 5G bearer network?

Since different customers have different optical transmission requirements, there are many types of optical modules. 25G optical modules can be divided into gray light modules, color light modules and BiDi single-fiber bidirectional optical modules. The following two categories are for everyone. Introduce them one by one.

1. Gray light module

Gray light module is a relatively conventional module, there are 25G SFP28 SR, 25G SFP28 LR, 25G SFP28 ER, 25G SFP28 SR uses vertical cavity surface emitting laser, needs to be used with 50/125µm OM3/OM4 multimode fiber, together with OM3 The transmission distance is 70 meters when used and 100 meters when used with OM4. 25G SFP28 LR and 25G SFP28 ER need to be used with single-mode OS2 fiber, and the farthest transmission distance can reach 10KM and 40KM respectively.

2. Color light module

25G SFP28 color optical module includes 25G SFP28 CWDM optical module and 25G SFP28 DWDM optical module. The optional working wavelength of 25G CWDM SFP28 optical module is 1271-1331nm, and the interval is 20nm. Its receiving and transmitting channels have built-in CDR circuits, and the maximum rate is up to 25.78Gbps, can support 10KM, 40KM transmission distance.

25G DWDM SFP28 series optical modules support C-band full wavelength (0.8nm interval, ie 100GHz), its devices adopt EML+APD scheme, the maximum rate is up to 25.78Gbps, the longest transmission distance is 80km, widely used in 25G Ethernet and CPRI /eCPRI.

3. BiDi single fiber bidirectional optical module

The 25G SFP28 BiDi optical module has the advantages of saving optical fiber resources and high-precision time synchronization. The transmitting end adopts the uncooled DFB TO form, the center wavelength is 1270nm/1330nm, and the receiving end adopts the high-sensitivity 25G PIN TO form, and the receiving wavelength is 1330nm/ 1270nm. The product follows the mature optical device coaxial packaging process platform to achieve single-fiber bidirectional, optical port rate of 25.78Gbps, and transmission distance up to 40 kilometers.