SFP+ 40km is a type of 10 Gigabit optical transceiver designed for long-distance data transmission up to 40 kilometers over single-mode fiber (SMF). In most cases, this term specifically refers to the 10GBASE-ER (Extended-Reach) standard defined by the IEEE for 10G Ethernet networks. The module consists of CWDM DFB Laser, PIN and Preamplifier in a high-integrated optical sub-assembly. Digital diagnostics functions. It includes 40GBASE QSFP+ modules, 40G Converter modules, 40G DACs/AOCs and their breakout cables. 40G QSFP+ Transceiver Module Series include SR4, BIDI, CSR4, PIR4, LX4, IR4, LR4,PLR4 and ER4.