Optimizing 5G Fronthaul Networks with 25G CWDM SFP28 Transceivers
Updated at Nov 10th 20241 min read
The 25G SFP28 CWDM transceiveris a fundamental component in transmission equipment and base stations, offering an effective solution for optimizing 5G fronthaul networks. This article provides a brief introduction to the 25G CWDM SFP28 transceivers, delving into their operational principles, advantages, and their significant impact on 5G fronthaul network performance.
What is 25G SFP28 CWDM Transceiver?
The 25G SFP28 CWDM transceiver plays a critical role in modern telecom, particularly in 5G fronthaul networks. Operating at 25 Gbps, the FS 25G CWDM SFP28 transceiver uses CWDM technology to transmit multiple signals over a single fiber, optimizing bandwidth and improving efficiency. Specifically tailored for 5G fronthaul, it supports 25G Ethernet and CPRI/eCPRI and offers a maximum transmission distance of 30 km over single-mode fiber, making it suitable for medium- to long-range applications within metropolitan and access networks. Fully compliant with SFP28 MSA, CPRI, and eCPRI standards, it typically operates within the 1270nm-1370nm and 1470nm-1570nm wavelength ranges, allowing flexible wavelength selection and efficient use of the optical spectrum.
If you want to know more about the differences between the 25G SFP28 CWDM module and other 25G SFP28 modules, you can check out this article: 25G SFP28 Transceiver Module Overview.
Figure 1: FS CWDM SFP28 Transceiver
What is 5G Transport Networks?
5G transport networks comprise fronthaul, midhaul, and backhaul, linking cell sites with one another, then with the core network, and ultimately with data centers.
Fronthaul: As 5G technology continues to evolve, the significance of "fronthaul" in the telecommunications industry is on the rise. This fiber-based link, integrated within the Radio Access Network (RAN) infrastructure, plays a pivotal role in achieving faster speeds and reduced latency. With the introduction of Distributed RAN (DRAN) and Centralized RAN (CRAN) approaches, base station components such as the Central Unit (CU), Distributed Unit (DU), and Active Antenna Unit (AAU) are undergoing substantial restructuring to meet evolving requirements. Fronthaul acts as the vital connection between the active antenna unit (AAU) and the distributed unit (DU), ensuring smooth communication and efficient data transmission. Innovations like the 25G CWDM SFP28 transceiver are essential for facilitating seamless communication and efficient data transfer across 5G fronthaul networks.
Midhaul: Midhaul is a crucial component of the telecommunications network, serving as the intermediary between the fronthaul and backhaul segments. It encompasses the transmission path from the Distributed Unit (DU) to the Centralized Unit (CU). In the context of 5G networks, base stations are structured into a distributed architecture. Here, the DU oversees the transmission and reception of wireless signals, while the CU manages communication with the core network. Acting as a vital link between these two units, midhaul facilitates the transfer of data from the DU to the CU for further processing and dissemination across the network.
Backhaul: The 5G transport network, apart from the fronthaul and midhaul, also includes the backhaul. This component consolidates access traffic from the Radio Access Network (RAN) and uses various technologies like Ethernet, microwave, and optical fiber to transport it to the central office or data center. The backhaul serves as a crucial link, connecting the fronthaul and midhaul to the core network, facilitating seamless data transmission across extensive distances.
5G transport networks are essential for seamless connectivity in telecommunications. Fronthaul enhances speed and reduces latency, midhaul acts as a link between fronthaul and backhaul, and backhaul consolidates and transports data to the core network. These segments are vital for efficient 5G deployments and reliable communication services.

Figure 2: 5G Transmission Networks Architecture
Applications of 25G CWDM SFP28 in 5G Fronthaul Network
In the early stages of 5G network setup, fronthaul mainly uses direct fiber links, along with high-frequency and extensive low-frequency coverage for extra access points. To maximize current fiber resources, CWDM optical modules are key. The 25G SFP28 CWDM solution selects 6 or 12 wavelengths from 18 specified in the ITU-T G.694.2 standard, ranging from 1271nm to 1611nm. By following this standard, optical transmission equipment from different vendors can work together in the same network to ensure the stability and reliability of the network and reduce problems caused by mismatches between equipment.
25G CWDM SFP28 6-Wavelength Solution
The 6-wavelength 25G CWDM solution opts for the initial 6 shorter wavelengths (1271nm~1371nm) due to the maturity of the industry chain and the lesser impact of transmitter dispersion penalties (TDP). It's widely agreed upon that the AAU side utilizes wavelengths of 1271nm, 1291nm, and 1311nm, while the DU side employs wavelengths of 1331nm, 1351nm, and 1371nm, as depicted in Fig.3. Additionally, the optical module on the AAU side requires cooled directly modulated lasers (DMLs) to meet industrial-grade standards.

Figure 3: 25G CWDM SFP28 6-Wavelength Solution
25G CWDM SFP28 12-Wavelength Solution
The 12-wavelength 25G CWDM solution addresses a mixed transmission scenario involving both 4G and 5G networks. To enhance reliability and reduce component costs, the wavelengths ranging from 1271nm to 1371nm operate at a 25Gbit/s data rate for 5G fronthaul networks, while the wavelengths from 1471nm to 1571nm operate at a 10Gbit/s data rate for 4G fronthaul networks. This arrangement, illustrated in Fig. 4, facilitates the smooth transition from 4G to 5G base stations. However, in practice, the 25G SFP28 connector takes precedence due to its compatibility with both 4G and 5G networks, making the 12-wavelength solution less commonly used in real-world scenarios.

Figure 4: 25G CWDM SFP28 12-Wavelength Solution
The integration of 25G CWDM SFP28 modules in 5G fronthaul networks streamlines fiber usage, guarantees equipment harmony, and eases the shift from 4G to 5G technologies. The tailored 6-wavelength and 12-wavelength solutions offer flexibility to meet diverse network demands effectively, ensuring the efficiency and future readiness of 5G fronthaul infrastructures.
Advantages of 25G CWDM Modules in 5G Fronthaul Network
When we talk about the choice of optical transceiver in 5G fronthaul network, short-distance transmission and more flexible deployment may be priority factors, so CWDM modules are usually more suitable. so we will briefly discuss some of the advantages of the 25G CWDM module in the 5G fronthaul network:
Cost-effective: CWDM technology allows multiple different wavelengths of signals to be transmitted over the same fiber optic cable, effectively utilizing fiber optic resources. In CWDM systems, the spacing between wavelengths is typically large (around 20nm), enabling the use of more affordable and readily available light sources. This feature reduces the cost of the system by optimizing resource utilization and leveraging cost-effective light sources.
High Performance: The 25G CWDM modules offer significantly higher performance compared to traditional optical networks. This ensures faster data transmission with lower latency, a critical feature for supporting 5G applications that demand high-speed communication and near-instantaneous data transfer.
Low Power Consumption: In 5G networks, where energy efficiency is crucial, the 25G CWDM SFP28 modules are designed with low power consumption in mind. This makes them ideal for 5G fronthaul applications, where reducing energy consumption without compromising performance is a key consideration for network operators.
Compatibility:The25G CWDM modules profiles are widely compatible with current and future network equipment. This broad compatibility ensures that network operators can seamlessly deploy 5G networks without concerns about integrating new technology with existing infrastructure. It simplifies upgrades and transitions as 5G is rolled out globally.
Flexibility and Scalability: Given the substantial and ever-increasing volumes of data typically associated with big data applications, networks must possess robust flexibility and scalability. By employing 25G CWDM modules, one can dynamically select different wavelengths for data transmission. Additionally, the relatively large wavelength spacing in CWDM makes it easier to add more wavelengths to expand the network, meeting the continuous growth demands of big data processing.
Data Security: In the domain of big data applications, handling and processing extensive volumes of sensitive data is routine, underscoring the critical importance of data security. 25G CWDM modules strengthens data transmission security by segregating data streams of varying wavelengths into separate channels. This segregation minimizes the risks of data leaks and interference, thereby enhancing the reliability and security of data transmission.
Overall, 25G CWDM modules are crucial for optimizing 5G fronthaul networks by offering high performance, low latency, cost efficiency, and scalability. They maximize fiber usage, reduce power consumption, and integrate easily with existing infrastructure. With flexible wavelength selection and enhanced data security, these modules are essential for supporting the growing demands of 5G applications, ensuring a robust, secure, and cost-effective network.
Conclusion
25G CWDM SFP28 uses CWDM technology to transmit multiple signals on a single high-efficiency optical fiber, providing an efficient data transmission solution for 5G fronthaul networks.This technology not only optimizes how bandwidth is used but also meets the high-speed and low-latency demands of 5G networks. Moreover, it enhances data transmission security by segregating data streams into separate channels based on different wavelengths. Overall, its use ensures comprehensive protection for network performance, flexibility, and security, laying a solid foundation for the future of 5G communication.