Multipath dispersion of a pulse of light in an optical fiber.

[Sauk]

Homework Statement

Multipath dispersion of a pulse of light in an optical fiber.
How is this problem solved?

 

[Lucky13T]

Multipath dispersion is can be solved by:

1) Making the fibre (core) very narrow.

2) By making the cladding which surrounds the core very close to the core refractive index. The closer the two refractive indexes the better as any light that is less than a certain angle will be lost therefore only light that is at the right angle, preferably straight to the optical fibre, reaches the receiver.

 

[Field of View]

Why does making the core narrower reduce multipath dispersion?

 

[MalachiK]

I've been thinking about this problem today, and I found this page as part of a search for more information.

At first I thought that it was obvious why reducing the width of the fibre would reduce the multipath dispersion. But having tried the problem with maths, I'm not so sure.

I've tried to calculate the maximum possible path difference along a fibre of length l and width d that has a maximim transmission angle of $$\theta$$ to the normal of the core cladding boundary. I've come up with an expression for this path difference in terms of the length of the fibre... <Attached are my scribbles>


The problem with this formulae is that the path difference becomes a larger fraction of the total length of the fibre as the width of the fibre gets smaller.

Can anyone tell me where my maths has gone wrong?

Thanks

 

[paranormal]

The problem of multipath dispersion in optical fibers can be solved using a combination of theoretical modeling and experimental techniques. Theoretical models, such as the Maxwell's equations, can be used to understand the propagation of light in the fiber and predict the effects of multipath dispersion. These models take into account factors such as the refractive index of the fiber, the geometry of the fiber, and the wavelength of the light being transmitted.

Experimental techniques, such as time-domain reflectometry and optical time-domain reflectometry, can be used to measure the actual dispersion of light in the fiber. These techniques involve sending a pulse of light through the fiber and measuring the time it takes for the pulse to travel through the fiber and reflect back. By analyzing the time delay and shape of the reflected pulse, the amount of dispersion can be determined.

Additionally, advanced signal processing techniques can be used to compensate for the effects of multipath dispersion in optical fiber communication systems. These techniques involve manipulating the transmitted signal to mitigate the effects of dispersion and improve the overall performance of the system.

In summary, solving the problem of multipath dispersion in optical fibers involves a combination of theoretical modeling, experimental measurements, and signal processing techniques. This multidisciplinary approach allows for a comprehensive understanding and effective management of multipath dispersion in optical fiber systems.