Single-fiber bidirectional optical modules are more expensive, but can save one fiber resource, which is a better choice for users with insufficient fiber resources. If the fiber resources are sufficient. Choosing between a 100G single-fiber (BiDi) and a dual-fiber optical module is a critical decision in network design, directly impacting cost, fiber resource utilization, and application suitability. This detailed guide provides a comparative analysis to help you select the optimal 100G transceiver. Single fiber modules (BiDi) use one fiber for both transmitting and receiving data. Dual fiber modules use two fibers. They are easier to set up and give steady communication. There are two main types: Single Fiber Bidirectional (SFB) Single Fiber Bidirectional Transmission enables two-way communication. In 100G optical modules, single-fiber modules save fiber resources through wavelength division multiplexing (WDM) technology, making them suitable for scenarios with limited fiber resources or long-distance transmission; dual-fiber modules have a simple structure and low cost, making them suitable. When designing or upgrading a fiber network, one key decision is whether to use dual-fiber or single-fiber (BiDi) optical modules.