Two 1-km fibers are spliced together. Each fiber has a 5-dB loss, and the splice adds 1 dB of loss. If the power entering is 2 m W, then how much power is delivered to the end of this combined transmission line?

Answer 1

Total loss = -5 + -5 + -1 = -11 db

10*Log(Po/Pi) = -11 db.
10*Log(Po/2) = -11
Log(Po/2) = -1.1
Po = 2*10^-1.1 = 0.159 mW.