Question
Download Solution PDFThe core refractive index and a relative refractive index difference of a multimode step-index fiber are specified as 1.5 and 2%, respectively. At operating wavelength of 1300 nm, the approximate number of propagating modes is 1000. The diameter of the fiber core is :
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFConcept:
The number of propagating modes in a multimode step-index fiber is approximately given by,
Where V is the normalized frequency (V-number), and is given by,
NA is the numerical aperture and is defined as,
Where, n1 = core refractive index, Δ = relative refractive index difference, λ = operating wavelength, a = core radius
Calculation:
Given:
n1 = 1.5, Δ = 2% = 0.02, λ = 1300 nm = 1.3 × 10-6 m, M = 1000
Calculate NA:
Now,
From,
Core diameter = 2a ≈
Correct Option:
The closest answer is: 3) 62 µm
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