Finisar’s FTL4E1QM1C QSFP+ transceiver modules are designed for use in 40 Gigabit Ethernet links and 4x10G OTN client interfaces over single mode fiber. They are compliant with the QSFP+ MSA1, IEEE 802.3bm 40GBASE-ER42 and OTU3 requirements specified in ITU-T Recommendation G.6953 as adapated to a 40km interface. Digital diagnostics functions are available via an I2C interface, as specified by the QSFP+ MSA. The optical transceiver is compliant per the RoHS Directive 2011/65/EU5. See Finisar Application Note AN-2038 for more details5.