Question

In an optical fibre, the power drops by a factor of 10 approximately every 30 km. If the transmit power is 0. 35 W, how far will a signal be transmitted before the power is attenuated to 350 μW?

Answer 1

• 30000 km

Explanation:

First convert the transmit power into μW, considering 1 W = 1000000 μW:

• 0.35 W = 0.35*1000000 μW = 350000 μW

Find how many factors of 10 the power dropped:

• 350000 / 350 = 1000

Find the distance:

• 1000*30 km = 30000 km