Cylindrical Fiber

Optical Communications

This set of Optical Communications Multiple Choice Questions & Answers (MCQs) focuses on “Cylindrical Fiber”.

1. A multimode step index fiber has a normalized frequency of 72. Estimate the number of guided modes.
a) 2846
b) 2592
c) 2432
d) 2136

2. A graded-index fiber has a core with parabolic refractive index profile of diameter of 30μm, NA=0.2, λ=1μm. Estimate the normalised frequency.
a) 19.32
b) 18.84
c) 16.28
d) 17.12

3. A step-index fiber has core refractive index 1.46 and radius 4.5μm. Find the cutoff wavelength to exhibit single mode operation. Use relative index difference as 0.25%.
a) 1.326μm
b) 0.124μm
c) 1.214μm
d) 0.123μm

4. A single-mode step-index fiber or multimode step-index fiber allows propagation of only one transverse electromagnetic wave.
a) True
b) False

5. One of the given statements is true for intermodal dispersion. Choose the right one.
a) Low in single mode and considerable in multimode fiber
b) Low in both single mode and multimode fiber
c) High in both single mode and multimode fiber
d) High in single mode and low in multimode fiber

6. For lower bandwidth applications ______________
a) Single mode fiber is advantageous
b) Photonic crystal fibers are advantageous
c) Coaxial cables are advantageous
d) Multimode fiber is advantageous

7. Most of the optical power is carried out in core region than in cladding.
a) True
b) False

8. Meridional rays in graded index fibers follow ____________
a) Straight path along the axis
b) Curved path along the axis
c) Path where rays changes angles at core-cladding interface
d) Helical path

9. What is the unit of normalized frequency?
a) Hertz
b) Meter/sec
c) Coulombs
d) It is a dimensionless quantity

10. Skew rays follow a ___________
a) Hyperbolic path along the axis
b) Parabolic path along the axis
c) Helical path
d) Path where rays changes angles at core-cladding interface

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