400G QSFP-DD optical module: technical analysis and application prospects

武汉格凌科技

400G QSFP-DD optical module: technical analysis and application prospects [Copy link]

400G optical modules are mainstream products in the optical communication industry. QSFP-DD is the most commonly used 400G optical module product package. This article introduces the common types of QSFP-DD optical modules: SR8, DR4, FR4, FR8, LR4, LR8, ER4, ER8 and ZR, analyzes the differences and application scenarios between each model, and compares QSFP-DD with QSFP112 and OSFP optical modules.

1. 400G QSFP-DD Optical Module Overview

400G QSFP-DD optical modules are mainly used in data centers and high-performance computing fields. QSFP-DD modules add additional signal channels based on QSFP to support higher data transmission rates.

2. Main types of 400G QSFP-DD optical modules

The main models of 400G QSFP-DD optical modules are: QSFP-DD SR8, QSFP-DD DR4, QSFP-DD FR4, QSFP-DD FR8, QSFP-DD LR4, QSFP-DD LR8, QSFP-DD ER4, QSFP-DD ER8, QSFP-DD ZR.

3. Differences between common types of 400G QSFP-DD

3.1 QSFP-DD FR4 and QSFP-DD FR8

400G QSFP-DD FR4 and 400G QSFP-DD FR8 optical modules are single-mode optical modules with CWDM4 wavelength and maximum transmission distance of 2km. The difference lies in the number of channels and applications.

Number of channels: On the electrical port side, QSFP-DD FR4 and QSFP-DD FR8 are both 8 channels 53Gbps, and on the optical port side

Supports 4 channels of 106Gbps, and FR8 supports 8 channels of 50Gbps.

Application: QSFP-DD FR4 optical modules are suitable for data centers, while QSFP-DD FR8 optical modules are suitable for high-performance computing.

3.2 QSFP-DD LR4 and QSFP-DD LR8

400G QSFP-DD LR4 and 400G QSFP-DD LR8 optical modules are long-distance transmission solutions with a maximum transmission distance of 10km. The main differences are:

Number of channels: QSFP-DD LR4 supports 4 channels at 106 Gbps, and QSFP-DD LR8 supports 8 channels at 53 Gbps.

Application: 400G QSFP-DD LR4 is used in scenarios such as 5G, cloud computing, and the Internet of Things, while 400G QSFP-DD LR8 is mainly used in data centers and telecommunication networks.

3.3 QSFP-DD ER4 and QSFP-DD ER8

400G QSFP-DD ER4 and 400G QSFP-DD ER8 optical modules are long-distance transmission solutions. "E" stands for Extended, which means extended transmission distance. The maximum transmission distance is 40km. The main differences are:

Number of channels: QSFP-DD ER4 supports 4 channels at 106 Gbps, and QSFP-DD ER8 supports 8 channels at 53 Gbps.

Application: ER4 is suitable for data center interconnection, Ethernet, IB interconnection, transmission network, etc.; ER8 is suitable for large-scale data center, wide area network and metropolitan area network and other application scenarios.

4. QSFP-DD application scenarios

4.1 Inside the data center

QSFP-DD SR8: Maximum transmission distance 100m; QSFP-DD DR4: Maximum transmission distance 100m. QSFP-DD DR4 and QSFP-DD SR8 are suitable for short-distance transmission within the data center, such as interconnection between servers or between racks.

4.2 Between data centers

QSFP-DD FR4/FR8: Maximum transmission distance 2km, suitable for connections between data centers and external networks, medium-distance communication networks, etc.

QSFP-DD LR4/LR8: Maximum transmission distance is 10km, commonly used for long-distance transmission between data centers.

QSFP-DD ER4/ER8: The maximum transmission distance is 40km, which is suitable for ultra-long distance transmission between data centers, such as cross-city interconnection.

QSFP-DD ZR: Maximum transmission distance is 80km, ultra-long distance transmission, such as inter-city interconnection and intercontinental transmission.

5. FAQ

5.1 Differences between QSFP-DD and QSFP112

QSFP-DD supports 8 channels of 53Gbps, with a total transmission rate of 424Gbps; QSFP112 has a transmission rate of up to 800G in the entire package, supports 4 channels of 112Gbps, with a total transmission rate of 448Gbps. Both QSFP112 and QSFP-DD are compatible with QSFP+/QSFP28.

5.2 Differences between QSFP and OSFP

OSFP (Octal Small Form Factor Pluggable) modules are larger than QSFP-DD. OSFP has 8 high-speed electrical channels and supports 200G, 400G and 800G rates. OSFP is also not backward compatible with QSFP+/QSFP28.