400G transceivers are introduced to cater to the ever-increasing demand for high-bandwidth data transfer in modern data centers and telecommunications networks. The market has seen various types of 400G optical transceivers to meet different application scenarios. This article will focus on the 400G optical modules and introduce the types and applications to help you choose among them.

400G SR4

400G SR4 is a high-speed transceiver standard, supporting 400Gbps over multimode fiber (MMF). It can transmit data for up to 100 meters via OM4 MMF at 850nm wavelength. The transmission distance is slightly shorter when used with OM3 MMF. 400GABSE-SR4 module transmits and receiver data by 4 parallel lanes, each carrying 100 Gbps to achieve 400 Gbps. The module typically applies an MTP/MPO-12 APC connector to match with 12 fiber cables, 4 of which are for transmitting, 4 are for receiving and the other 4 are inactive for redundancy.

Algannics provides two 400G SR4 form factors: QDD-400G-SR4 and OSFP-400G-SR4. Both are ideal for high-speed data center 400G point-to-point applications. Besides, they can be used for breakout solutions. 

The 400GBASE-SR4 QSFP-DD supports 400G SR4 to 2x 200G SR2 (2 of 200G per channel) breakout connections and 400G SR4 to 4x 100G SR (4 of 100G per channel) breakout connections. The 400GBASE-SR4 OSFP module supports both 4x 100G SR Ethernet and InfiniBand NDR. 6C-QSFP-DD-SR4 has a maximum link length of 100m on OM4 fiber with FEC while 6C-OSFP-400G-SR4 is designed for short-range transmission within 50 meters.

400G SR8

400G SR8 is a high-speed transceiver standard, supporting 400Gbps over multimode fiber (MMF). It can transmit data for up to 100 meters via OM4 MMF and up to 70 meters with OM3 MMF on 850nm central wavelength. The 400GBASE-SR8 module transmits and receives data using 8 parallel lanes, each carrying 50 Gbps to achieve 400 Gbps. The module connectors have two variants. One variant utilizes a single-row MPO-16 connector to match 16 fiber cables, with eight fibers for transmitting and 8 for receiving. Another variant employs the MPO-24 connector. The schematic diagram is shown in the image below.

Algannics 400G SR8 includes QDD-400G-SR8 and OSFP-400G-SR8, with two form factors for selection. Both are designed with MPO-16 APC connectors and share the same maximum transmission distance of up to 100 meters. They can be used for 400G SR8 to 8x 50G SR breakout connectivity solutions.

400G DR4

400G DR4 is a high-speed transceiver standard for data center and telecommunications applications requiring longer-distance data transmission. Unlike the former two multimode fiber transceivers, 400G DR4 is a single-mode module. 400GBASE-DR4 supports 400Gbps data transmission for a 500m reach over single-mode fiber (SMF). It is designed with an APC MPO-12 connector to carry four parallel channels of 100G capacity each, using 1310nm EML lasers.

Algannics provides QDD-400G -DR4 and OSFP-400G-DR4 for up to 500m transmission solution. The 400GBASE-DR4 QSFP-DD is compliant with QSFP-DD MSA, IEEE 802.3bs 400GBASE-DR4 protocol, and 400GAUI-8 standard. 400GBASE-DR4 OSFP complies with OSFP MSA, IEEE 802.3-2022 400GBASE-DR4 optical interface, IEEE 802.3ck-2022: 400GAUI-4, 200GAUI-2, 100GAUI-1 C2M electrical interface. These 400G DR4 modules support 4x 100G breakout to QSFP28 100G-DR applications.

400G SR4, 400G SR8, and 400G DR4 are designed for high-speed short-range applications, making them suitable for various data center and telecommunications scenarios. Their different specifications and capabilities allow for flexibility in deployment based on specific needs.

Questions and Answers about 400G SR4, 400G SR8, and 400G DR4

Q1: What are the primary differences between 400G SR4, 400G SR8, and 400G DR4 transceivers?

A1: The primary differences lie in their design and application:

• 400G SR4: Designed for short-range, high-speed data transmission over multimode fiber (MMF). It uses 4 parallel lanes, each carrying 100 Gbps, and supports up to 100 meters with OM4 MMF.
• 400G SR8: Also for short-range applications over MMF but uses 8 parallel lanes, each carrying 50 Gbps, which allows for up to 100 meters with OM4 MMF. It supports more versatile breakout configurations.
• 400G DR4: Designed over single-mode fiber (SMF) for longer distances. It uses 4 parallel lanes, each carrying 100 Gbps, and supports up to 500 meters.

Q2: Which transceiver should I choose for a data center with a maximum link distance of 70 meters?

A2: For a data center with a maximum link distance of 70 meters, the 400G SR8 transceiver is a suitable choice. It supports up to 70 meters with OM3 MMF and provides versatile breakout options.

Q3: Can 400G SR4 transceivers be used for breakout applications?

A3: Yes. 400G SR4 transceivers can be used for breakout applications. The 400GBASE-SR4 QSFP-DD, for instance, supports 400G SR4 to 2x 200G SR2 and 400G SR4 to 4x 100G SR breakout connections.

Q4: What type of fiber and connector are used with 400G DR4 transceivers?

A4: The 400G DR4 transceivers use single-mode fiber (SMF) and are designed with an MTP/MPO-12 APC connector. They support up to 500 meters reach using 1310nm EML lasers.

Q5: Which transceiver has the highest power consumption, and what is the value?

A5: The 400G SR8 transceivers have the highest power consumption, with each module consuming up to 12W.

Q6: What modulation format do all three types of transceivers use?

A6: All three types of transceivers (400G SR4, 400G SR8, and 400G DR4) use PAM4 (Pulse Amplitude Modulation with 4 levels) modulation format.

Q7: What are the typical applications for 400G SR8 transceivers?

A7: The 400G SR8 transceivers are typically used for short-range data center applications, providing 400G to 8x 50G breakout solutions and supporting InfiniBand NDR.

Q8: If my application requires a reach of up to 500 meters, which transceiver should I consider?

A8: For applications requiring a reach of up to 500 meters, you should consider the 400G DR4 transceiver, as it is designed for long-distance data transmission over single-mode fiber.

Q9: Are there any specific standards or protocols that 400G DR4 transceivers comply with?

A9: Yes, the 400G DR4 transceivers comply with several standards and protocols, including QSFP-DD MSA, IEEE 802.3bs 400GBASE-DR4, 400GAUI-8, OSFP MSA, IEEE 802.3-2022 400GBASE-DR4 optical interface, and IEEE 802.3ck-2022 400GAUI-4, 200GAUI-2, 100GAUI-1 C2M electrical interface.

Q10: Can 400G SR4 transceivers be used with OM3 fiber?

A10: Yes, 400G SR4 transceivers can be used with OM3 fiber, but the transmission distance will be slightly shorter compared to OM4 fiber, typically supporting distances up to 70 meters with OM3 MMF.

By considering your application’s specific requirements and the characteristics of each transceiver type, you can make an informed decision to optimize your data center or telecommunications network performance.Algannics also provides middle-to-long-reach 400G optical modules, including 2km 400G XDR4, 2km 400G FR4, 10km 400G PLR4, LR4, LR8, and 40km 400G ER8. If you have any questions when choosing from the 400G modules or need quotations, please contact [email protected].