Number of reflections in an Optical fibre

In summary, the number of reflections made by a light entering a 2m long optical fibre cable with an angle of incidence of 3.43 degrees and a core diameter of 60μm and refractive index of 1.48 is 36368.48. The refractive index is important for ensuring total internal reflection.
  • #1
Rahulr2k
3
0
How many reflections will be made by a light entering a 2m long optical fibre cable. If the angle of incidence with the axis of the core is 3.43° . Given that the core diameter and refractive index are 60μm and 1.48 respectively

I got the answer as 36368.48 is this correct?

L=2m

d=60μm

sinθ= n(air)/n(fibre) = 0.67567

∴ θ= 42.50664°

tanθ= 0.9165
∴No. of reflections = L/(d tan θ )
= 36368.48
 
Last edited:
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  • #2
Hi Rahulr2k. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif

I would have thought that the refractive index is irrelevant, other than needing to be sufficient to ensure that there is total internal reflection?

Does that 3.43 figure have units of degrees?
 
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  • #3
yes...3.43 degrees
 

1. How many reflections occur in an optical fibre?

The number of reflections in an optical fibre depends on the length and curvature of the fibre, as well as the angle of incidence of the incoming light. Typically, multiple reflections occur as the light bounces back and forth between the walls of the fibre, resulting in hundreds or even thousands of reflections.

2. Why are reflections important in optical fibres?

Reflections are important in optical fibres because they allow the light to travel long distances without significant loss of signal strength. The multiple reflections help to keep the light contained within the fibre, allowing it to reach its destination with minimal loss of energy.

3. Do the number of reflections affect the quality of the signal in an optical fibre?

Yes, the number of reflections can affect the quality of the signal in an optical fibre. Too many reflections can result in signal degradation or distortion, which can impact the overall performance of the fibre. This is why careful design and maintenance of optical fibres is important to minimize the number of reflections.

4. Can the number of reflections be controlled in an optical fibre?

Yes, the number of reflections can be controlled in an optical fibre through various techniques such as using specialized coatings or materials to reduce the amount of light that reflects off the walls of the fibre. Other techniques involve changing the shape or size of the fibre to minimize reflections.

5. How do reflections contribute to the total distance that light can travel in an optical fibre?

Reflections play a significant role in the total distance that light can travel in an optical fibre. As light reflects back and forth within the fibre, it effectively extends the distance the light can travel before it dissipates. This allows for longer distances to be covered without the need for additional repeaters or amplifiers.

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