The correct answer is: B. 0.2 to 1 ns/km
Graded index fiber is a type of optical fiber in which the refractive index of the core decreases gradually from the center to the cladding. This graded index profile causes light to travel in a zigzag path through the fiber, which reduces modal dispersion and allows for higher bandwidth and longer transmission distances than step-index fiber.
The pulse broadening value for graded index fiber is the amount of time it takes for a pulse of light to travel through a length of fiber. This value is affected by the fiber’s length, core diameter, and refractive index profile. In general, the pulse broadening value for graded index fiber is in the range of 0.2 to 1 ns/km.
Option A is incorrect because it is too high. The pulse broadening value for graded index fiber is typically much less than 1 ns/km.
Option C is incorrect because it is too low. The pulse broadening value for graded index fiber is typically greater than 0.2 ns/km.
Option D is incorrect because it is too wide. The pulse broadening value for graded index fiber is typically much less than 8 ns/km.