Module 5 : Signal Distortion on Optical Fibers - Dispersion
Lecture 1 : Signal Distortion on Optical Fibers - Dispersion
Inter-Modal Dispersion
The inter-modal dispersion is due to difference in velocity of different modes inside a fiber. Obviously, the inter-modal dispersion takes place in a multi-mode fiber.
It has been shown earlier that the optical rays launched at different angles give different modal fields. The inter-modal dispersion can therefore be approximately calculated using the ray model.
The inter-modal dispersion is approximately given as
The unit of inter modal-dispersion is ps/Km.
The magnitude of inter-modal dispersion is much larger compared to the chromatic dispersion. Therefore the chromatic dispersion is neglected while calculating the dispersion in a multi-mode fiber.
