Question

Calculate the V number of an optical fibre having numerical aperture 0.25 and core diameter 20 μm, if its operating wavelength is 1.55 μm

Answer 1

NA = 0.25
Core diameter = 20 μm
λ0= 1.55 μm

Formula: V = ᴨd / λ0 ×NA

V = 3.14×20×10^-6 /1.55 ×10^-6 ×0.25
V = 10.13