Which fiber type has a single light path and supports long distances from several kilometers up to 100 kilometers?

Which fiber type has a single light path and supports long distances from several kilometers up to 100 kilometers?

• A. Single-Mode Fiber
• B. Multimode Fiber
• C. Cat6a
• D. 10GBASE-LR

Answer: (A)

Single-mode fiber uses a single light path because its core is very small, about 8–10 micrometers in diameter. This tiny core keeps light traveling in essentially one route, which minimizes modal dispersion—the spreading of a signal as light follows multiple paths. With less dispersion, the signal can maintain integrity over long distances, making it suitable for links spanning several kilometers up to around 100 kilometers when paired with appropriate transmitters and amplifiers. By contrast, multimode fiber has a larger core (around 50–62.5 micrometers) that supports many light paths, causing more modal dispersion and limiting how far the signal can travel at high data rates. The other options don’t represent a fiber type: one is a copper Ethernet cable, and the other is a specific long-reach optical transceiver standard rather than a fiber type.

Single-mode fiber uses a single light path because its core is very small, about 8–10 micrometers in diameter. This tiny core keeps light traveling in essentially one route, which minimizes modal dispersion—the spreading of a signal as light follows multiple paths. With less dispersion, the signal can maintain integrity over long distances, making it suitable for links spanning several kilometers up to around 100 kilometers when paired with appropriate transmitters and amplifiers. By contrast, multimode fiber has a larger core (around 50–62.5 micrometers) that supports many light paths, causing more modal dispersion and limiting how far the signal can travel at high data rates. The other options don’t represent a fiber type: one is a copper Ethernet cable, and the other is a specific long-reach optical transceiver standard rather than a fiber type.