Which of the following is a valid pairing of a multi-mode fiber core diameter and cladding, among those commonly listed?

Which of the following is a valid pairing of a multi-mode fiber core diameter and cladding, among those commonly listed?

• A. 50 Microns with 90 Micron Cladding
• B. 120 Microns with 150 Micron Cladding
• C. 100 Microns with 140 Micron Cladding
• D. 180 Microns with 210 Micron Cladding

Answer: (C)

In multimode fiber, the core carries the light and is surrounded by a cladding that keeps the light guided by total internal reflection. Cable makers list standard core/cladding pairs, and the cladding diameter must be larger than the core. Common multimode pairings you’ll see are 50/125, 62.5/125, and 100/140. Among the options, 100 microns core with 140 microns cladding matches the established, cataloged pairing for larger-core multimode fibers, making it a valid combination. The other options use cladding sizes that don’t align with typical standard pairings for those core sizes, so they aren’t commonly listed.

In multimode fiber, the core carries the light and is surrounded by a cladding that keeps the light guided by total internal reflection. Cable makers list standard core/cladding pairs, and the cladding diameter must be larger than the core. Common multimode pairings you’ll see are 50/125, 62.5/125, and 100/140.

Among the options, 100 microns core with 140 microns cladding matches the established, cataloged pairing for larger-core multimode fibers, making it a valid combination. The other options use cladding sizes that don’t align with typical standard pairings for those core sizes, so they aren’t commonly listed.