Pluggable optical module
Beginner
A small box that plugs into the front of a switch and turns electrical signals into light and back.
Novice
A hot-swappable transceiver in a standard form factor (such as QSFP-DD or OSFP) that slots into a cage on the switch’s front panel. It contains the electronics, lasers and light detectors for one port.
Expert
Contains a host-side retimer/DSP, laser drivers, modulators or directly modulated lasers, photodiodes and TIAs, plus management. Standard electrical interface (AUI) to the host, standard optical interface (an IEEE PMD such as DR or FR) to the fiber. A field-replaceable unit.
Explained in Optics (Systems).
See also: DSP (in an optical module), Linear-drive pluggable optics (LPO), Co-packaged optics (CPO).