Multimode fiber is generally less expensive because it can use LEDs and other lower-cost light sources. Which statement best reflects this?

Multimode fiber is generally less expensive because it can use LEDs and other lower-cost light sources. Which statement best reflects this?

• A. Multimode fiber is generally less expensive due to LEDs
• B. Multimode fiber is more expensive due to laser sources
• C. Multimode fiber is rarely used in LANs
• D. Multimode fiber is used for extremely long distances

Answer: (A)

The main idea here is that the cost difference comes from the light source used to transmit signals. Multimode fiber can use inexpensive LEDs (and similar lower-cost sources) to launch light into the fiber. LEDs are cheaper to produce and drive than the laser diodes typically used with single-mode fiber, and the associated transmitter electronics are simpler. The combination of a larger core in multimode fiber and the forgiving alignment needed for LED light makes the overall transceiver cheaper, which keeps the system costs down for short-haul networks like those in LANs. That’s why this statement best reflects the situation: multimode fiber is generally less expensive because it can use LEDs and other lower-cost light sources. The other ideas don’t fit because lasers and laser-based transceivers are more expensive and are usually paired with single-mode fiber, multimode isn’t intended for extremely long distances, and multimode fiber is indeed commonly used in LANs for its cost and practicality.

The main idea here is that the cost difference comes from the light source used to transmit signals. Multimode fiber can use inexpensive LEDs (and similar lower-cost sources) to launch light into the fiber. LEDs are cheaper to produce and drive than the laser diodes typically used with single-mode fiber, and the associated transmitter electronics are simpler. The combination of a larger core in multimode fiber and the forgiving alignment needed for LED light makes the overall transceiver cheaper, which keeps the system costs down for short-haul networks like those in LANs.

That’s why this statement best reflects the situation: multimode fiber is generally less expensive because it can use LEDs and other lower-cost light sources. The other ideas don’t fit because lasers and laser-based transceivers are more expensive and are usually paired with single-mode fiber, multimode isn’t intended for extremely long distances, and multimode fiber is indeed commonly used in LANs for its cost and practicality.