Sky Optics 400G QSFP-DD ER4 is an ultra-long-reach single-mode transceiver based on 400GBASE-ER4 standard, adopting 1271/1291/1311/1331nm CWDM4 wavelength scheme. It is equipped with cooled high-power EML laser chips and high-sensitivity PIN receivers, supporting 425Gbps high-speed signal stable transmission up to 30km over G.652 single-mode fiber with duplex LC-UPC interface.

Different from ordinary LR4 modules, ER4 adopts refrigerated laser optimization design, with higher optical power and stronger anti-attenuation capability. The module has a power consumption of less than 10W, operates stably in 0℃-70℃ commercial temperature range, and supports CMIS4.0 protocol and full DDM real-time monitoring. It has super link loss tolerance and can adapt to complex long-distance fiber wiring and aging line scenarios.

As a 30km ultra-long-distance 400G transmission solution, it is mainly used for cross-city MAN interconnection, remote base station backhaul, large-scale data center cross-region networking and enterprise ultra-long-distance network convergence. It solves the distance limit of ordinary long-range modules and is the preferred high-stability solution for 400G ultra-long-distance wired transmission.