Fiber optic links can use two fibers for full duplex (bidirectional) links.

• A. Sometimes
• B. True
• C. False
• D. Not Applicable

Answer: (B)

Two fibers can provide full duplex operation because simultaneous two‑way communication requires separate paths for each direction. By dedicating one fiber to transmit in one direction and another fiber to transmit in the opposite direction, each path can carry its own signal without sharing the same medium. This setup eliminates interference between the two directions and allows full bandwidth to be used in both directions at the same time. It’s a common and valid way to implement bidirectional links in fiber networks. While there are other methods to achieve bidirectional communication on a single fiber (such as using different wavelengths or time-division), the statement that two fibers can be used for full duplex is correct.