LPO Pluggable Optical Module Test Report

LPO modules have been tested for lane calibration, interoperability, and power-efficient operation, demonstrating simplified tuning, low latency, and compatibility with modern data center ASICs.Overview of LPO Testing

Linear Pluggable Optics (LPO) modules are designed to shift signal processing from the module to the host ASIC, replacing DSPs with high-linearity analog components such as transimpedance amplifiers (TIAs) and driver chips. This architecture reduces power consumption and latency while maintaining high-speed performance for short-reach, high-density data center links . Testing focuses on verifying that these modules can operate reliably across multiple lanes, support host-based signal processing, and maintain interoperability with different switch or NIC platforms.

Key Test Results

1. Lane Calibration and Signal Integrity CIG's ECOC 2023 presentation highlighted that single-lane tuning can calibrate all 8 lanes of a switch port, simplifying operations and reducing costs . Tests confirmed that LPO modules can maintain signal integrity across multiple lanes, even at speeds up to 200G per lane, provided the host ASIC can tune each port and the module driver compensates for impairments.
2. Interoperability Testing Eoptolink demonstrated LPO modules in OSFP, OSFP-RHS, QSFP-DD, and QSFP112 form factors, showing that modules can operate across ports with varying insertion losses and that two FIR settings are sufficient for reliable operation . Interoperability tests also confirmed that LPO modules can coexist with DSP-based modules in the same system, supporting plug-and-play deployment.
3. Power and Latency Performance LPO modules consistently showed lower power consumption compared to DSP-based optics due to the absence of onboard digital processing . Latency measurements indicated improved synchronization in AI/ML clusters and GPU fabrics, which is critical for high-performance computing environments.
4. Standards Compliance LPO modules follow the 100G-DR-LPO MSA specification, supporting 53.125 GBd PAM4 optical interfaces, single-mode fiber links up to 500 meters, and host-module electrical interfaces compatible with DSP-based SerDes and RS(544,514) FEC . Testing ensures compliance with IEEE 802.3 and OIF CEI-112G-LINEAR-PAM4 standards, enabling Ethernet-like links with 1, 2, 4, or 8 lanes.

Summary

The LPO test reports indicate that these modules are suitable for dense, low-latency, and power-efficient data center interconnects. Key findings include:

• Simplified lane calibration and tuning for multi-lane ports
• Reliable interoperability with different module vendors and host ASICs
• Reduced power consumption and latency compared to DSP-based modules
• Compliance with MSA and IEEE/OIF standards for high-speed optical links These results demonstrate that LPO modules are a viable solution for modern data centers, particularly in leaf-spine networks and AI/ML clusters where efficiency, scalability, and low latency are critical .