Astep index fiber has a numerical aperture of na = 0.1. the refractive index of

diameter = 9.951 × m

Explanation:

given data

NA = 0.1

refractive index = 1.465

wavelength = 1.3 μm

to find out

What is the largest core diameter for which the fiber remains single-mode

solution

we know that for single mode v number is

V ≤ 2.405

and v =

here r is radius    

so we can say

   = 2.405

put here value

   = 2.405

solve it we get r

r = 4.975979 × m

so diameter is = 2  ×  4.975979 × m

diameter = 9.951 × m