LINK-PP LQD-DM31800XDR8C 800G XDR8 QSFP-DD 8 x 100G PAM4 1310nm 2km Dual MPO-12/APC SMF Transceiver Module

Product Specifications

LINK-PP LQD-DM31800XDR8C 800GBASE-XDR8 QSFP-DD Optical Transceiver 1310nm 2km Dual MTP/MPO-12 APC for Hyperscale Data Center Interconnects

The LINK-PP LQD-DM31800XDR8C is a high-performance, MSA-compliant 800GBASE-XDR8 (Extended Data Rate) QSFP-DD optical transceiver engineered for large-scale AI/ML backend fabrics, High-Performance Computing (HPC) clusters, and expansive data center campus environments. Operating over Single-Mode Fiber (SMF), this hot-pluggable module bridges distances up to 2km, utilizing a highly flexible Dual MTP/MPO-12 APC interface designed to natively fractionalize 800G ports without the need for complex conversion cables.

Integrating eight parallel transmission and receiving lanes utilizing 100G PAM4 (Pulse Amplitude Modulation 4-level) electrical and optical signaling, the module achieves an aggregate data rate of 850Gbps (8x 106.25Gbps). Fully compliant with IEEE 802.3cu-2021, IEEE 802.3ck-2022, QSFP-DD MSA HW Rev 7.0, and CMIS 5.0, it utilizes high-performance 1310nm EML lasers and integrated DSP-based Forward Error Correction (FEC) to ensure pristine signal integrity. By leveraging the Dual MPO-12 form factor, data center architects can seamlessly deploy scalable 800G point-to-point links or direct 2x 400GBASE-XDR4 connections, maximizing routing silicon utilization across sprawling campuses.

Application Topologies and Deployment Scenarios

The transition to 800G Ethernet requires optics that can overcome severe insertion loss over long physical distances while maintaining high port density. The Dual MPO-12 design of this XDR8 module solves major physical layer routing challenges in modern hyperscale environments.

Native 2x 400GBASE-XDR4 Breakout Architecture

The primary architectural advantage of the Dual MPO-12 design is native, hardware-level fractionalization. Instead of deploying expensive, custom MPO-16 to 2x MPO-12 breakout y-cables, network engineers can plug two standard 12-fiber MPO cables directly into the front of this single 800G transceiver. This allows an 800G QSFP-DD core router port to operate seamlessly as two physically distinct 400G-XDR4 links, connecting directly to 400G spine/leaf switches up to 2km away.

Hyperscale Campus Interconnects (2km Reach)

Standard DR8 optics are limited to 500 meters, which is often insufficient for bridging separate data center halls or inter-building campus networks. The 800GBASE-XDR8 utilizes a higher-power optical budget to transmit up to 2,000 meters over OS2 single-mode fiber. This enables lossless, microsecond-latency RDMA (RoCEv2) traffic to flow seamlessly between isolated GPU training clusters and centralized storage arrays across massive cloud facilities.

High-Density 8x 100G-FR Server Connectivity

For extreme-density Edge or AI server access, this module supports an 8x 100G breakout topology. By deploying two MPO-12 to 4x Duplex LC single-mode breakout cables, a single 800G switch port can provide direct 100GBASE-FR (2km) connectivity to eight individual AI compute nodes or NVMe storage arrays located in distant rows, collapsing the network aggregation layer.

Physical Layer Design and Optical Performance Optimization

Transmitting 100Gbps per lane over 2 kilometers of single-mode fiber requires sophisticated optical engineering to overcome chromatic dispersion and signal attenuation. LINK-PP transceivers integrate advanced optical engines to guarantee a robust physical layer.

8x 100G PAM4 EML Transmitter Architecture

To drive single-mode fiber over extended distances, this module utilizes premium 1310nm EML (Electro-absorption Modulated Lasers). Compared to standard DMLs or VCSELs, EMLs provide a significantly narrower spectral width and lower chirp. This makes them highly resilient to the chromatic dispersion penalties inherent in 100G PAM4 transmission over 2km fiber runs. The receiving end employs a matched high-bandwidth PIN array to accurately decode the complex PAM4 optical eye.

The Dual MTP/MPO-12 APC Single-Mode Interface

To support 8 TX and 8 RX lanes, this transceiver features two separate optical receptacles. Crucially, because single-mode 100G PAM4 signals are extraordinarily sensitive to optical return loss (back-reflection), the module utilizes APC (Angled Physical Contact) interfaces. The 8-degree angled polish ensures any reflected light is diverted safely into the fiber cladding, maintaining low Relative Intensity Noise (RIN) and preserving link stability.

Advanced DSP, Inbuilt FEC, and Thermal Management

Unlike shorter-reach modules that rely entirely on the host switch for error correction, the LQD-DM31800XDR8C features a powerful integrated DSP with Inbuilt FEC (Forward Error Correction) capabilities. This local processing significantly cleans up signal degradation over the 2km span. Furthermore, the module is engineered within a QSFP-DD Type 2A housing featuring premium die-cast thermal pads, ensuring the high-power EMLs and DSP remain thermally stable (0°C to 70°C) without forcing switch chassis fans into thermal runaway.

Multi-Vendor Compatibility and CMIS 5.0 Diagnostics

Managing a 2km 800G single-mode fabric requires advanced software interfaces. This transceiver supports the latest Common Management Interface Specification to provide unprecedented visibility into the extended link state.

Open-Standards MSA Compatibility

Engineered for universal open-standards deployments, the LQD-DM31800XDR8C undergoes rigorous EEPROM coding and hardware validation. It guarantees plug-and-play interoperability in MSA-compliant 800G switching platforms, white-box networking hardware (e.g., Edgecore, Celestica), and routing systems running open-source operating systems like SONiC, avoiding proprietary vendor lock-outs.

CMIS Rev 5.0 Management Interface

Moving far beyond legacy SFF-8472 DOM, this module is fully compliant with CMIS 5.0. This advanced interface provides a robust state machine for module initialization, allowing the host switch to manage firmware upgrades, configure datapath DSP parameters, and negotiate power classes before enabling the long-reach EML lasers.

Per-Lane Real-Time Telemetry

Network engineers can actively monitor the health of all 16 parallel channels (8 TX / 8 RX). Telemetry includes independent TX Bias Current, TX Optical Power, and RX Optical Power for every individual lane. This granular visibility is absolutely critical in 2km campus environments, allowing for proactive identification of degraded splices, dirty fiber end-faces, or micro-bends before they cause a hard link failure.

Selection Guide and Deployment Considerations

Deploying 800GBASE-XDR8 optics introduces strict single-mode cabling rules. Follow these critical engineering guidelines to prevent hardware damage and link failures.

The Dual MPO-12 APC Single-Mode Cabling Requirement (Crucial Trap)

This is the most common deployment mistake in high-density optical networks. Legacy multi-mode MPO cables are typically PC/UPC (flat-polished). You MUST use two MTP/MPO-12 APC (Angled) Single-Mode cables for this 800G transceiver. Ensure the cables are explicitly designated for Single-Mode (typically yellow jacket) with APC polish (typically green connectors). Forcing a flat UPC MTP cable into this module will physically crush the internal lens array and permanently destroy the transceiver.

Inbuilt FEC and Host Interaction

While this module features Inbuilt FEC to handle the 2km optical link budget, 100G/lane PAM4 still requires strict FEC adherence. Ensure your host switch is properly configured (typically KP4 FEC enabled on the host port) to align with the transceiver's DSP negotiation, preventing unexpected BER (Bit Error Rate) failures.

Choosing Between XDR8 (2km) and DR8 (500m)

• XDR8 (This Module): 2km reach. Essential for connecting separate data center halls, inter-building campus links, or deployments with multiple high-loss patch panels in the optical path.
• DR8: 500m reach. Sufficient for intra-building spine-to-leaf interconnects where the total optical loss budget is strictly controlled.