Question

A multimode graded index fibre exhibits total pulse broadening of $0.1\, \mu s$ over a distance of $1.5\, km$. What is the maximum possible band width on the link assuming no inter symbol interference?

• A. $10 \,MHz$
• B. $7.5\, MHz$
• C. $5 \,MHz$
• D. $2.5 \,MHz$

Answer 1

Answer: (C)

$5 \,MHz$

Answer 2

The maximum possible optical band width is equivalent to the maximum possible bit rate (for return to zero pulses). It is given by $B_{T} = \frac{1}{2\tau } = \frac{1}{2\times0.1\times 10^{-6}} = 5\,MHz$