Cisco 400G QSFP-DD 400GBASE-FR4 Transceiver, 2 km Duplex SMF

Cisco lists the QDD-400G-FR4-S as a 400G QSFP-DD transceiver for 400G-FR4, reaching 2 km over duplex single-mode fiber. It follows IEEE 802.3cu for 400GBASE-FR4 and the 100G Lambda MSA, and its electrical side meets 400GAUI-8 (CEI-56G-VSR-PAM4).

The signal travels on four CWDM wavelengths, 1270, 1290, 1310 and 1330 nm, and the module multiplexes and demultiplexes them internally, so the link uses one fiber pair. Forward error correction is done on the host platform, not in the module. The fiber is G.652 single-mode and the connector is duplex LC; Cisco supports only patch cords with PC or UPC polish for this optic, and APC is not required.

Cisco gives the per-lane average transmit power as -3.2 to 3.5 dBm and the average receive power as -7.3 to 3.5 dBm, with the receive minimum marked informative only. Maximum supported insertion loss is 4 dB, pre-FEC bit error ratio is 2.4x10^-4, and the laser is Class 1. Maximum power consumption is 12 W.

Cisco shows this optic interoperating at 2 km and 4 dB with the QDD-2X400G-FR4 and the QDD-400G-LR4-S. The LR4-S is the 10 km duplex single-mode version in the same family, with the same 1270 to 1330 nm wavelength set and LC connector, so choose FR4 when 2 km is the longest span.

Browse the Cisco modules category, or see the QSFP-100G-LR4-S 100G LR4 module for a 100G duplex LC option.