800G Co-packaged Photonics Test Report

The 800G co-packaged photonics test report validates transmitter and receiver performance for 800G-LR4 modules, confirming DGD tolerance, TDECQ, OMA, and extinction ratio compliance with baseline specifications.Overview of 800G Co-Packaged PhotonicsCo-packaged optics (CPO) integrate the optical engine directly with or adjacent to the switch ASIC, reducing electrical trace lengths, lowering latency, and significantly cutting power consumption—up to 70% compared to pluggable optics in 1.6T networks . Silicon photonics platforms, such as STMicroelectronics' PIC100, enable high-volume production of 800G and 1.6T optical modules using CMOS-compatible processes on 300mm wafers, supporting hyperscale AI data center fabrics . This architecture improves switch port density and reduces serialization delay, critical for RDMA/RoCE workloads.Test MethodologyThe 800G-LR4 OSFP transceivers were tested using a Short Stress Pattern Random Quaternary (SSPRQ) with 65,535 symbols . Differential Group Delay (DGD) was emulated digitally by adding delayed copies of the original signal waveform, followed by an 11-tap Feed-Forward Equalizer (FFE). The tests conservatively assumed two extreme fiber DGD sections to evaluate worst-case performance.Key Test MetricsDGD Tolerance: The modules met the DGD tolerance levels reported in prior baseline studies, confirming robustness against polarization mode dispersion .Transmitter Power and Extinction Ratio: Measurements validated compliance with 800G-LR4 baseline specifications, ensuring sufficient optical power and signal integrity.OMA (Optical Modulation Amplitude): Confirmed to meet baseline requirements, supporting reliable high-speed transmission.TDECQ (Transmitter and Dispersion Eye Closure Quaternary): Verified under DGD conditions, indicating the module's ability to maintain signal quality over long distances.Receiver Performance: Additional validation results, including receiver sensitivity and error performance, are expected in follow-up reports .Implications for Data CentersThe validated 800G co-packaged photonics modules enable AI data centers to scale beyond 400G per link while reducing power consumption and latency . The soldered CPO modules require careful operational planning, as failed modules necessitate line card replacement rather than hot-swapping, representing a tradeoff between performance and maintainability.ConclusionThe 800G co-packaged photonics test report confirms that the modules meet critical performance metrics for high-speed optical networking, including DGD tolerance, TDECQ, OMA, and extinction ratio. These results support deployment in hyperscale AI data centers, leveraging silicon photonics and CPO architectures to achieve high bandwidth, low latency, and energy-efficient operation .