FTTH Application-Grade 100G Active Optical Device Selection Guide

Selecting 100G active optical devices for FTTH requires understanding QSFP28 transceivers, active optical cables, reach, fiber type, and deployment architecture to ensure optimal performance and compatibility.

Key Considerations for 100G FTTH Deployments

1. Deployment Architecture: FTTH networks can use home-run, centralized split, distributed split, or blended architectures. The choice affects the type of optical devices needed at the central office (CO) or headend (HE) and the fiber distribution strategy . 2. Transceiver Form Factors:

• QSFP28 is the most common 100G form factor, supporting four lanes at 25 Gbps each, yielding 100 Gbps payload. It can also support breakout into four 25G connections .
• CFP/CFP2/CFP4 modules are alternatives for longer reach or specific OTN applications . 3. Optical Technology and Reach:
• SR4/PSM4: Short-reach multimode or single-mode, typically up to 100–500 meters.
• LR4/CWDM4/ER4/ZR4: Long-reach single-mode transceivers, supporting distances from 2 km to 80 km .
• 100G-DR/FR/LR: Single-lambda PAM4 modules for 100G Ethernet or OTU4, with reach from 500 m to 10 km . 4. Connector Types:
• LC connectors are common for single-mode or multimode fiber.
• MTP/MPO connectors are used for parallel optics like SR4 or PSM4 . 5. Active Optical Cables (AOCs) and DACs:
• AOCs provide cost-effective short-reach solutions with integrated transceivers, ideal for data center interconnects.
• DACs are suitable for very short distances (<10 m) and low-power applications . 6. Compatibility and Standards:
• Ensure compliance with IEEE 802.3ba 100GBASE standards, QSFP28 MSA, and ITU-T G.959.1/G.709 for OTU4 applications .
• QSFP28 modules are backward-compatible with QSFP+ ports for 40G, but QSFP28 modules cannot operate in legacy QSFP+ ports . 7. Environmental and Reliability Factors:
• Industrial-grade modules support extended temperature ranges.
• RoHS-compliant and factory-tested connectors ensure long-term reliability .

Practical Selection Tips

• Short-reach FTTH links: Use 100G-DR or SR4 QSFP28 modules with multimode fiber.
• Medium to long-reach FTTH links: Use LR4, CWDM4, or ER4 single-mode modules depending on distance.
• High-density CO/HE deployments: Prioritize QSFP28 modules for compact, high-throughput ports.
• Future-proofing: Consider QSFP-DD or 400G-ready modules if planning network upgrades beyond 100G . By evaluating reach, fiber type, connector, form factor, and compliance, network designers can select the optimal 100G active optical devices for FTTH deployments, ensuring high performance, scalability, and cost efficiency.