Technologies and Products – Created November 20, 2025
The Optical Internetworking Forum (OIF) has released a new implementation agreement defining 112 Gb/s Retimed Transmitter Linear Receiver (RTLR) electrical and optical interface to help meet rising data centre and AI demands with greater interoperability and power savings.
The OIF-EEI-112G-RTLR specification defines a high-speed, energy-efficient 112 Gb/s chip-to-module electrical interface that connects retimed optical transmitters with linear optical receivers, sometimes referred to as ‘half retimed optical links.’ It supports Ethernet C2M 100 Gb/s and OIF CEI-112G-VSR-PAM4 16 dB channels, operating in the 36-56 GSym/s range for full Ethernet compatibility.
By eliminating the need for a receive DSP in the optical module and leveraging signal processing already available in the host device, the IA helps reduce power, cost and design complexity while maintaining interoperability and performance across vendors — a critical need in AI architectures.
“Across the ecosystem, OIF heard a clear message — the industry needs robust lower power links that are IEEE compliant,” said OIF Physical and Link Layer (PLL) Working Group Energy Efficient Interfaces (EEI) Vice Chair (Ranovus) Jeff Hutchins. “This IA reflects that input, advancing energy efficiency without sacrificing link quality or compatibility. It reinforces that OIF is where collaboration and technical leadership deliver the interoperability specifications needed for AI-driven, high-performance networks.”
At ECOC 2025, OIF’s multi-vendor interoperability demonstration showcased technologies spanning 400ZR, 800ZR, Multi-span Optics, Common Electrical I/O (CEI) — including CEI-448G and CEI-224G — Co-Packaging, CMIS and Energy Efficient Interfaces (EEI).
RTLR technology was featured as part of OIF’s EEI track, illustrating how retimed, half-retimed and unretimed pluggable optics interoperate across vendors. The RTLR portion specifically highlighted how OIF’s work bridges electrical and optical design to enable lower power, reduced complexity and real-world, multi-vendor interoperability — validating the framework defined in this new IA.
The EEI-112G-RTLR IA builds on OIF’s CEI-112G-PAM4 foundation and aligns fully with relevant IEEE 802.3 standards. The specification details general requirements, electrical and optical specifications, test methodologies and parameter definitions.
Originally published here