Question

Optical power of 3mW is launched into an optical fibre of length 200m. If the power emerging
from other end is 0.6mW, calculate the fibre attenuation​

Answer 1

Given that,

Input power = 3 mW

Output power = 0.6mW

Length = 200 m

We need to calculate the fiber attenuation

Using formula of attenuation

$\alpha=\dfrac{10}{l}log(\dfrac{P_{in}}{P_{out}})$

Where, $P_{in}$=input power

$P_{out}$=output power

Put the value into the formula

$\alpha=\dfrac{10}{200\times10^{-3}}\log{\dfrac{3}{0.6}}$

$\alpha=34.94\ db/km$

Hence, The fiber attenuation is 34.94 db/km.