Selection Guide for Safe City-Level Single-Fiber Bidirectional 100G

Single-fiber bidirectional (BiDi) 100G modules enable full-duplex 100Gbps transmission over a single fiber, optimizing fiber usage and reducing deployment costs in urban networks.

Key Considerations for Selection

1. Module Type and Form Factor

• QSFP-100G-SR1.2: Short-reach, duplex LC interface, supports 70–150m over OM3/OM4/OM5 multimode fiber, compatible with 400G breakout mode for future upgrades .
• QSFP28-BIDI-100G: BiDi transceiver using WDM to transmit and receive on different wavelengths over a single fiber, ideal for metro and data center interconnects .
• SFP28 BiDi: Compact, single-fiber solution for 25–100G links, suitable for campus, building-to-building, or metro networks . 2. Wavelength Pairing and WDM Technology
• BiDi modules rely on wavelength division multiplexing (WDM), transmitting on one wavelength (e.g., 1330nm) and receiving on another (e.g., 1270nm) through the same fiber .
• Always deploy complementary pairs: the transmit wavelength of one module must match the receive wavelength of the other to ensure full-duplex communication . 3. Fiber Type and Distance
• Multimode Fiber (MMF): OM3, OM4, or OM5 for short-reach links (up to 150m for SR1.2 BiDi modules), .
• Single-Mode Fiber (SMF): Required for longer metro or city-level links; check module specifications for maximum reach.
• Consider link loss, connector type (LC/SC), and fiber quality to maintain signal integrity. 4. Data Rate and Device Compatibility
• Ensure the module supports the intended data rate (100G) and is compatible with the switch or router port (QSFP28, QSFP+, or SFP28), .
• Verify backward compatibility if upgrading from 10G/40G infrastructure. 5. Operational and Safety Considerations
• Use certified modules tested for interoperability and reliability to prevent network downtime .
• Monitor temperature, optical power, and diagnostics using modules with digital diagnostic monitoring (DDM) for safe operation.
• Plan for redundancy and fiber management to minimize service disruption in urban deployments. 6. Applications
• Metro and city networks: Efficiently connect multiple buildings or data centers with limited fiber availability .
• 5G transport networks: High-capacity backhaul between base stations and core networks .
• Data center interconnects (DCI): Cost-effective, low-latency 100G links for disaster recovery and resource pooling .
• High-definition video and live broadcasting: Stable 4K/8K transmission with minimal signal loss .

Summary Recommendations

• Choose BiDi modules for single-fiber deployment to save fiber resources and reduce cabling complexity.
• Match wavelength pairs and ensure device compatibility.
• Select fiber type based on distance and link requirements.
• Use certified, monitored modules to maintain safe and reliable operation.
• Plan for future scalability, such as 400G breakout support, to extend network life without major infrastructure changes . By following these guidelines, city-level networks can achieve high-speed, cost-efficient, and reliable 100G connectivity while optimizing existing fiber infrastructure.