Sky Optics 400G QSFP-DD FR4 is classic CWDM4 mid-reach single-mode module designed per 400GBASE-FR4 standard with four fixed CWDM wavelengths of 1271/1291/1311/1331nm. Adopting four-channel EML laser and PIN receiver array plus PAM4 modulation, it achieves 425Gbps full-duplex transmission, supporting stable 2km long-distance transmission over G.652/G.657 standard single-mode fiber with duplex LC-UPC interface.

This QSFP-DD hot-pluggable transceiver features moderate power consumption within 8W, supporting 0℃-70℃ commercial temperature stable operation. It is fully compatible with CMIS4.0 protocol, integrates complete I²C DDM real-time diagnosis function. The CWDM4 coarse wavelength division multiplexing design avoids complex coherent devices, balancing low cost and stable transmission performance with strong on-site anti-interference capability.

As the mainstream 2km mid-reach 400G solution, FR4 cancels MPO multi-core wiring and adopts universal duplex LC interface, which is more suitable for traditional single-mode fiber wiring scenarios. It is widely used for data center building interconnection, park cross-building networking, medium-distance enterprise IDC uplink transmission, and is the preferred cost-effective solution for 400G medium-distance fixed-point networking.