Question

EXERCISE 1.3-2 Numerical Aperture of the Graded-Index Fiber. Consider a graded-index fiber with the index profile in (1.3-12) and radius a. A tay is incident fro a nto te fibe a its center, making an angle with the fiber axis (see Fig. 1.3-8). Show, in the paraxial Figure 1.3-8 Acceptance angle of a graded-index optical fiber approximation, that the numerical aperture is Numerical Aperture (Graded-Index Fiber) where ea is the maximum angle for which the ray trajectory is confined within the fiber. Compare this to the numerical aperture of a step-index fiber such as the one discussed in Exercise 1.2-5. To make the comparison fair, take the refractive indices of the core and cladding of the step-index fiber to be ni-no and n2-nd(1- гаг)',, nd(1-wa2),

Answer 1

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