BiDirectional SFP optical modules transmit data over a single optical fibre (simplex).
CWDM SFP optical modules transmit data in the second and third transmission windows (1270-1610nm).
DWDM SFP optical transceivers are available in 100GHz and 50GHz versions. They enable transmission over a range of 1565.5nm to 1528.77nm.
A copper transceiver is a device equipped with a RJ45 port which facilitates transmission over a copper cable through a fibre optic port.