Answer 8

The bandwidth of an optical fiber is limited primarily by the time-smearing caused by multi-mode transmission along paths of different lengths within the fiber.

Multimode step index fiber has the lowest cost, but it smears the signal the most because it makes no attempt to control multipath.

Multimode graded index fiber has a change of density from the center to the edge that causes the light away from the center to travel faster. This causes the mutliple paths to have similar transmission times, reducing the smearing of the signal.

Single mode fiber is very narrow, with very little room for multipath, so it has the least amount of smearing. However, it is the most expensive to manufacture and requires more expensive emitters and detectors at each end.

Contributor: Naveen PN

Published: November-2002