What is graded-index fiber?

Graded-Index Fiber

Graded-index fiber is a type of optical fiber designed to minimize signal distortion caused by modal dispersion. It achieves this by varying the refractive index of the core in a gradual manner, rather than having a uniform refractive index.

Construction and Principle

The core of a graded-index fiber has a high refractive index at the center which gradually decreases towards the outer edge. This variation in the refractive index creates a lensing effect, causing light rays to follow a curved path and travel at different speeds depending on their distance from the fiber axis.


  • Reduces modal dispersion
  • Increases bandwidth compared to step-index fibers
  • Improves signal quality over long distances


  • Long-distance telecommunications
  • High-speed data transmission networks
  • Local Area Networks (LANs)

Comparison with Step-Index Fiber

Feature Graded-Index Fiber Step-Index Fiber
Refractive Index Profile Gradual change Sharp change
Modal Dispersion Lower Higher
Bandwidth Higher Lower

In summary, graded-index fiber is an advanced type of optical fiber that offers superior performance for high-speed and long-distance communication by effectively managing modal dispersion through its unique refractive index profile.

Back to blog

Leave a comment