Question: Sketch and explain construction of graded index optical fibre.

Electronics > Sem 6 > Computer Communication Networks

modified 9 months ago  • written 10 months ago by gravatar for Manali Ghorpade Manali Ghorpade30

Multimode Graded Index Fiber

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  • Graded Index Fiber is a type of fiber where the refractive index of the core is lower toward the outside of the fiber.
  • The core in a graded-index fiber has an index of refraction that radially decreases continuously from the center to the cladding interface.
  • As a result, the light travels faster at the edge of the core than in the center as shown in Figure. Different modes travel in curved paths with nearly equal travel times.
  • This greatly reduces modal dispersion in the fiber.


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  • Graded-index fibers bends the rays inward and also allows them to travel faster in the lower index of refraction region. This type of fiber provides high bandwidth capabilities.
  • As a result, graded-index fibers have bandwidths which are significantly greater than step-index fibers, but still much lower than single-mode fibers.
  • Typical core diameters of graded-index fibers are 50, 62.5 and 100 ┬Ám.
  • The main application for graded-index fibers is in medium-range communications, such as local area networks.
written 9 months ago by gravatar for Manali Ghorpade Manali Ghorpade30
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