Linear-drive pluggable optics (LPO)
Beginner
A plug-in light module with the signal-cleaning chip removed, so it uses less power. The switch chip does that work instead.
Novice
An optical module without a DSP. Its driver and receiver amplifiers pass the signal through linearly, and the switch chip’s own SerDes equalizes the whole path, electrical and optical, end to end. Saves power and delay, but works only with strong host SerDes and is harder to mix and match.
Expert
Linear driver and linear TIA only; no CDR. The link budget spans host SerDes → host channel → module → fiber → module → host channel → host SerDes, so interoperability must be defined end to end (LPO MSA, OIF linear interfaces). Half-retimed (LRO) variants keep a DSP on transmit only.
Explained in Optics (Systems).
See also: DSP (in an optical module), Pluggable optical module, Co-packaged optics (CPO).