IEEE 802.3 25GBase-ER
25GBase-ER is an interface for 25 Gigabit Ethernet( 25GbE). It is a fiber optic interface for single mode fibers.
From the interface designation ER, which stands for Extended Reach, it is clear that it is an interface that works with an extra-long wavelength of 1,550 nm. In addition, the 25GBase-ER can bridge distances of up to 40 km, on two optical fibers and one lane. It is described in IEEE 802.3cc.
The 25GBase-ER interface operates with 64B66B coding and monomode fibers. The wavelength range at 1,550 nm is used as the optical window. The light signals are generated by VCSEL lasers and transmitted at a data rate of 25 Gbit/s. The Gigabit interface 25GBase-ER uses an SFP module as optical transceiver( OT).