Optical module is the basic unit to realize photoelectric conversion in 5G network. It is widely used in wireless and transmission equipment. It is an important part of 5G construction. The capital pressure of 5G large-scale construction leads to cost sensitivity, and the cost of optical module accounts for more than 50% of 5G pre transmission equipment. The industry has carried out the research on the low-cost scheme of 5G optical module, made great progress, and a variety of solutions have emerged. Among them, 25G SFP28 CWDM has won the favor of most experts.

CWDM has 18 wavelength choices, but the supply of the middle 6 waves is relatively blank due to the water peak effect of the early optical fiber. The first six waves (1270nm-1370nm) in the 25gbit/s CWDM scheme can adopt the low-cost configuration of uncooled DML laser and pin detector, and has mature industrial chain support, which has great advantages and can well meet the needs of six wave base stations. The 25G CWDM optical module of ETU-LINK optical communication has 6 CWDM channels, with optional wavelengths of 1270nm, 1290nm, 1310nm, 1330nm, 1350nm and 1370nm, and can support a transmission distance of 10KM at most.

In order to better understand 25G SFP28 CWDM，ETU-LINK talks about the comparison between 25G SFP28 CWDM and other XWDM schemes in this blog.

Comparison with 25G SFP28 DWDM

25G DWDM can provide 45 channels that meet the requirements of DWDM ITU 100GHz Grid (currently developing 25G DWDM SFP28 laser with a distance of 40 km). We know that in addition to optical amplifiers, incoherent DWDM systems below 100G usually need dispersion compensation modules to compensate the line dispersion cost.

Therefore, the cost of 25G DWDM SFP28 scheme is much higher than that of 25G SFP28 CWDM. This is why when 12 or fewer 25G channels need to be interconnected between stations and the distance is less than 40 km, we recommend the scheme of 25G SFP28 CWDM.

Comparison with 25G SFP28 LAN WDM

25G lwdm SFP28 ranges from 1269.23nm to 1318.35nm and has 12 channels. This is the same number of channels available in the 25G SFP28 CWDM. The optical components of 25G SFP28 LWDW are relatively new and more expensive than those of 25G SFP28 CWDM. However, the main advantage of the 25G SFP28 LWDM is that it supports a range of 40 km and industrial temperatures (from - 40 ° C to + 85 ° C). 25G SFP28 LWDM 40 km lasers are becoming more and more widely used in the market. Due to the competition between 25G SFP28 CWDM and 25G SFP28 LWDM, both types of transceivers will become cheaper.

Comparison with 25G SFP28 MWDM

MWDM is medium wavelength division multiplexing. Based on the first six mature products of CWDM scheme, the 25 Gbit/s NWDN scheme expands these six waves from the original six waves to 12 waves by shifting their wavelengths to the left or right respectively.

MWDM/LWDM adopt 12 wavelength configuration, and DWDM wavelength tunable scheme has the advantages that can not be replaced by other schemes such as port independence and wavelength adaptive characteristics. Therefore, if the technology of low-cost tunable laser is mature in the future, DWDM scheme will also be a more appropriate choice. Although different XWDM technologies have their own advantages and disadvantages, the current main technical direction is to adopt 6-wavelength CWDM configuration.