LINK-PP LQD-DM31800-DR8C 800G DR8 QSFP-DD 8 x 100G PAM4 1310nm 500m Dual MPO-12/APC SMF Transceiver Module

Product Specifications

LINK-PP LQD-DM31800-DR8C 800GBASE 2xDR4 / DR8 QSFP-DD Optical Transceiver 1310nm 500m Dual MTP/MPO-12 APC for Hyperscale Data Centers

The LINK-PP LQD-DM31800-DR8C is a high-performance, MSA-compliant 800GBASE 2xDR4 / DR8 QSFP-DD optical transceiver engineered for hyperscale data center interconnects, massive AI/ML backend fabrics, and high-density routing infrastructures. Operating over OS2 Single-Mode Fiber (SMF), this hot-pluggable module bridges physical distances up to 500 meters, utilizing a highly flexible Dual MTP/MPO-12 APC interface designed to natively support dual 400G-DR4 links without requiring complex breakout Y-cables.

Architected with an 8x 100G-PAM4 electrical interface and a Dual 4x 100G-PAM4 optical engine, 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 to ensure pristine signal integrity across 500m single-mode spans. By leveraging the Dual MPO-12 form factor, data center architects can seamlessly deploy scalable 800G point-to-point links or direct 2x 400GBASE-DR4 connections, maximizing routing silicon utilization across modern cloud facilities.

Application Topologies and Deployment Scenarios

The transition to 800G Ethernet requires optics that can overcome severe insertion loss over single-mode fiber while maintaining high port density. The Dual MPO-12 design of this 500m DR8 module solves major physical layer routing challenges in modern hyperscale environments.

Native 2x 400GBASE-DR4 Breakout Architecture

The primary architectural advantage of the Dual MPO-12 interface is native, hardware-level fractionalization. Instead of deploying custom MPO-16 to 2x MPO-12 conversion breakout 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-DR4 links, connecting directly to 400G leaf switches or 400G SmartNICs up to 500m away.

Reusing Base-8 Single-Mode Infrastructure

Many modern data centers have standardized on Base-8 MPO structured cabling (utilizing 8 fibers out of a 12-fiber MPO connector for 400G DR4 optics). Deploying standard MPO-16 800GBASE-DR8 optics typically requires tearing out this infrastructure to install new MPO-16 trunks. This dual-receptacle module allows operators to achieve 800G point-to-point links by simply aggregating two existing single-mode MPO-12 trunk cables, dramatically reducing upgrade CAPEX and installation time.

Hyperscale AI/ML Spine-to-Leaf Interconnects

In massive AI training clusters, the physical distance between leaf switches and core spine routers often exceeds the 50-meter limit of multi-mode fiber. Deployed over OS2 single-mode fiber, this module bridges 800G Top-of-Rack (ToR) switches to spine layers, ensuring microsecond-latency, lossless RDMA (RoCEv2) traffic across spans up to 500 meters.

Physical Layer Design and Optical Performance Optimization

Transmitting 100Gbps per lane over 500 meters of single-mode fiber requires highly sophisticated optical engineering. LINK-PP transceivers integrate advanced optical engines and DSP (Digital Signal Processing) to guarantee a robust physical layer.

Dual 4x 100G PAM4 EML Transmitter Architecture

To drive single-mode fiber effectively, this module incorporates two independent optical sub-assemblies (TOSA/ROSA), each driven by premium 1310nm EML (Electro-absorption Modulated Lasers) operating on 4-lane 100G PAM4 modulation. EMLs provide a significantly narrower spectral width and lower chirp than standard DMLs or VCSELs, making them highly resilient to chromatic dispersion penalties over 500m single-mode runs. The receiving end employs matched high-bandwidth PIN arrays to accurately decode the 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 Thermal Management and DSP Power Efficiency

Driving eight EML lasers and a high-performance 800G DSP generates significant heat. Engineered within a QSFP-DD Type 2/2A housing, this module features premium die-cast thermal pads that efficiently wick heat away from critical chip-level components. This ensures stable commercial operation (0°C to 70°C) and prevents thermal throttling in high-density 800G switch chassis.

Multi-Vendor Compatibility and CMIS 5.0 Diagnostics

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

Open-Standards MSA Compatibility

Engineered for universal open-standards deployments, the LQD-DM31800-DR8C 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 allows 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 2xDR4/DR8 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 (or UPC single-mode cables) will cause severe reflection or physical damage. 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.

Mandatory Host-Side FEC (Forward Error Correction)

PAM4 modulation at 106.25Gbps per lane inherently produces bit errors over 500 meters of fiber before correction. The 500m reach of this transceiver is strictly dependent on KP4 FEC (Clause 119) being enabled on the host switch port. Operating this module without host-side FEC is not supported and will result in massive packet loss (BER failure).

Choosing Between Dual MPO-12 and Single MPO-16 Form Factors

• Dual MPO-12 (This Module): Ideal if your primary goal is fractionalization (connecting directly to two independent 400G-DR4 switches), or if you already have Base-8 / Base-12 single-mode MPO cabling installed in your data center and want to reuse it.
• Single MPO-16: Ideal for native 800G point-to-point connections where you are pulling brand new fiber trunks and want to minimize cable bulk at the switch faceplate.