Linear Receive Optics

Overview

Linear Receive Optics (LRO) — also called Transmit Retimed Optics — is a hybrid pluggable transceiver architecture that uses a DSP on the transmit side while keeping the receive side linear (no DSP retiming). This design balances the efficiency and robustness spectrum between fully retimed DSP transceivers and pure LPO: the receive path benefits from LPO's power savings, while the DSP-retimed transmit provides greater signal robustness than pure LPO under challenging channel conditions.

At 800G DR8, LRO measures 8.5 W (10.6 pJ/bit) versus 7.5 W for LPO and 13.0 W for DSP. At 1.6T 2xDR4, LRO is 15.0 W (9.4 pJ/bit) versus 10.0 W for LPO and 21.0 W for DSP. LRO has been demonstrated at 1.6T with all 8 lanes well below 1E-4 BER spec, confirming ecosystem feasibility at that data rate.