Why can 25G SFP28 LWDM optical modules be used in 5G fronthaul networks?
The 25G SFP28 LWDM optical module conforms to the IEEE802.3ba standard, it can transmit 25G rate, and can also flexibly upgrade the network to 50G or 100G.
1. Save fiber resources
The full name of LWDM is LAN WDM. The 25G SFP28 LWDM module has 12 wavelengths, all of which belong to the O-band. Eight wavelengths are the standard wavelengths that divide the spectrum of the O-band according to 800GHz, and the remaining four wavelengths are multiplexed with 25G. The four wavelengths of the CWDM optical module are 1269.23nm, 1332.41nm, 1313.73nm and 1291.10nm. Like the 25G WDM module, the 25G SFP28 LWDM optical module can also use WDM technology to multiplex multiple wavelengths onto a pair of fibers, which can save a lot of fiber resources.
2. Stable data transmission
The wavelength interval of the 25G SFP28 LWDM optical module is 4nm, which is much narrower than that of the 25G CWDM optical module, so a large wavelength shift will occur. Normally, the operating temperature of the SFP28 LWDM optical module is -40°C ~ 85°C, and 1°C will produce a wavelength shift of about 1nm. Since the temperature span of the 25G LWDM optical module is 125°C, the SFP28 LWDM may generate 12.5nm. wavelength shift.
In order to ensure the stability of transmission, TEC temperature control is essential for 25G SFP28 LWDM optical modules, because it can form current through the movement of charge carriers in the conductor, when the DC passes through two different conductor materials, the contact end The phenomenon of heat absorption or heat release will be generated, which can make the laser work at the set temperature for a long time and stably, thereby stabilizing the wavelength, so that the 25G SFP28 LWDM optical module can ensure stable and accurate data transmission in harsh environments.
3. Lower deployment cost
The 25G SFP28 LWDM module can also be multiplexed on a single fiber like the 25G CWDM and 25G DWDM modules, and its cost is lower, mainly in its structural design. In the design of the receiver, due to the large dispersion of the SFP28 25G CWDM optical module, the transmission stability is at risk, so a more expensive APD receiver is needed to ensure the stability of transmission, but the wavelength of the SFP28 LWDM module is located in the low dispersion area, and the receiving Only the PIN receiver can be used by the terminal to meet the transmission requirements, thus saving the transmission budget. In the design of the laser, compared with the SFP28 DWDM module, the 25G SFP28 LWDM optical module does not necessarily need to use an expensive EML laser like the SFP28 DWDM module, but a relatively cheap DML laser. In this way, while ensuring the transmission, it can better control the cost, making it an ideal and efficient solution in the 5G fronthaul network.
