Assume that the optical power transmitted by a 62.5/125 multimode fiber is distributed uniformly across its core. If this fiber is perfectly coupled (i.e., the two fibers are aligned and abutted) to a 50/125 fiber, what is the percent of power that is lost?
When a 62.5/125 multimode fiber is perfectly coupled to a 50/125 multimode fiber, there will be a power loss due to the difference in core sizes. The core area of the 62.5/125 fiber is larger than that of the 50/125 fiber. Specifically, the cross-sectional area of the 62.5/125 fiber core is (π * (62.5/2)^2) and the cross-sectional area of the 50/125 fiber core is (π * (50/2)^2). The ratio of these two areas gives the fraction of the power that is coupled from the 62.5/125 fiber to the 50/125 fiber. This ratio is (50/62.5)^2, which equals 0.64. This means that 64 percent of the power from the 62.5/125 fiber is successfully coupled into the 50/125 fiber, indicating a 36 percent power loss.
It should be 0 percent . why they chose number B ?
It is not 0 because the recieving fiber is 50 from a 62.5 and not the other way around.
We need an explanation .
It is a typo, it should be 26.915% Multimode mismatch in which a 50/125 recieves a signal from a 62.5/125 has a core and power loss of 5.7dB.