Q1: What is a QSFPDD-400G-FR4 module?
A: The QSFPDD-400G-FR4 is a QSFP-DD form-factor transceiver that supports 400 Gbps Ethernet over single-mode fiber (SMF) using four CWDM wavelengths (1271/1291/1311/1331 nm) with a duplex LC optical interface.
Q2: What is the maximum supported transmission distance?
A: Supports up to 2 km over G.652 SMF when host-side forward error correction (FEC) is enabled, as per IEEE 802.3cu specification.
Q3: What connector and fiber type does it use?
A: Uses a duplex LC connector over single-mode fiber (9/125 µm SMF).
Q4: Is the module compatible across different brands?
A: Yes. It adheres to QSFP-DD MSA and IEEE 802.3cu, and is compatible with vendors such as Cisco, Arista, Juniper, Huawei, FS.com, ProLabs, and Edge-Core, provided the device accepts generic optics.
Q5: Is the module hot-swappable?
A: Yes. The QSFP-DD form factor supports hot-plug insertion and removal without powering down the host system.
Q6: Does it support breakout into lower-rate links?
A: Yes—commonly supports 4×100G DR1 breakout via appropriate cabling, allowing interoperability with 100G-DR, FR, and LR optics up to specified distances.
Q7: Does QSFPDD-400G-FR4 support diagnostics (DDM/DOM)?
A: Yes. Supports digital diagnostic monitoring (CMIS/CMIS-compliant) via I²C for monitoring power, temperature, voltage, and status.
Q8: What is the aggregate and per-lane data rate?
A: Operates at a total of ~425 Gbps aggregate, using four 106.25 Gbps PAM4 lanes; internally interfaces with 8×50 Gbps PAM4 on electrical side (400GAUI-8).
Q9: Typical power consumption?
A: Typically consumes ≤ 12 W, often around 10 W depending on variant and traffic load.
Q10: Operating temperature range?
A: Standard commercial modules operate from 0 °C to 70 °C; some specifications indicate up to –40 °C to +85 °C for storage or extended versions.
Q11: Which standards does it comply with?
A: Conforms to IEEE 802.3bs (400GBASE-SR8/FR4 spec), IEEE 802.3cu (400G-FR4), QSFP-DD MSA, 100G Lambda MSA FR4 spec, and 400GAUI-8 / CEI-56G-VSR-PAM4 electrical interface standard.
Q12: How to verify compatibility with my network device?
A: Confirm that your switch or NIC supports 400G-FR4 QSFP-DD optics, allows generic optics, and host-side FEC is enabled. Many vendors list part numbers like QDD-400G-FR4-S for compatibility.
Q13: What are typical applications for this module?
A: Suitable for mid-range 400G data center interconnects, cross-building links, rack-to-rack backbone, and breakout into 100G channels in enterprise or cloud environments.
Q14: What is the optical power budget per lane?
A: Typical launch power per CWDM lane ~−3.3 to +3.5 dBm, with receiver sensitivity around < −7.7 dBm, sufficient for 2 km SMF link using FEC.
Q15: Are industrial or extended-temperature variants available?
A: Yes. Some vendors offer modules with wider temperature support, though typical versions operate within 0–70 °C, with storage tolerance up to –40 °C to +85 °C.