Deck 8: Various Aspects of Optical Fiber Design and Performance

Question 1

An Si-O bond with a Young's modulus of 9*10¹⁰Nm^?1 have an elliptical crack of depth 7nm. The surface energy is 2.29 J. Estimate fracture stress for silica fiber.

A)4.32*10⁹nm^?1
B)6.32*10⁹nm^?1
C)5.2*10⁹nm^?1
D)3*10⁹nm^?1

Answer 1

4.32*10⁹nm^?1

Question 2

Calculate percentage strain at break for a Si-O bond with a fracture strength of 3.52*10¹⁰Nm^?1 and Young's modulus of 9 *10⁹nm^?1.

A)3.1 %
B)2.8 %
C)4.5 %
D)3.9 %

Answer 2

3.9 %

Question 3

Stress corrosion must be considered while designing and testing optical fiber cables.

Answer 3

True

Question 4

Which statistics are used for calculations of strengths of optical fibers?

A)edwin statistics
B)newton statistics
C)wei-bull statistics
D)gamma statistics

Question 5

. ____________ results from small lateral forces exerted on the fiber during the cabling process.

A)attenuation
B)micro-bending
C)dispersion
D)stimulated emission

Question 6

Microscopic meandering of the fiber core axis that is micro-bending is caused due to

A)environmental effects
B)rough edges of the fiber
C)large diameter of core
D)polarization

Question 7

How many forms of modal power distribution are considered?

A)one
B)two
C)three
D)four

Question 8

What does micro-bending losses depend on?

A)core material
B)refractive index
C)diameter
D)mode and wavelength

Question 9

The fiber should be________________ to avoid deterioration of the optical transmission characteristics resulting from mode-coupling-induced micro-bending.

A)free from irregular external pressure
B)coupled with plastic
C)large in diameter
D)smooth and in a steady state

Question 10

The diffusion of hydrogen into optical fiber affects the ______________

A)transmission of optical light in the fiber
B)spectral attenuation characteristics of the fiber
C)core of the fiber
D)cladding of the fiber

Question 11

__________ can induce a considerable amount of attenuation in optical fibers.

A)micro-bending
B)dispersion
C)diffusion of hydrogen
D)radiation exposure

Question 12

The radiation-induced attenuation can be reduced through photo-bleaching.

Question 13

The losses due to hydrogen absorption and reaction with fiber deposits can be temporary.

Question 14

The losses caused due to hydrogen absorption mechanisms are in the range of

A)20 db/km to25 db/km
B)10 db/km to15 db/km
C)25 db/km to50 db/km
D)0 db/km to5 db/km

Question 15

The cable must be designed such that the strain on the fiber in the cable does not exceed__________

A)0.002%
B)0.01%
C)0.2%
D)0.160%

Question 16

How many categories exists in case of cable design?

A)two
B)three
C)one
D)four

Question 17

How many types of buffer jackets are used in fiber buffering?

A)three
B)one
C)two
D)four

Question 18

Loose tube buffer jackets exhibits a low resistance to movement of the fiber.

Question 19

An inclusion of one or more structural members in an optical fiber so as to serve as a cable core foundation around which the buffer fibers may be wrapped is called _____________

A)attenuation
B)splicing
C)buffering
D)stranding

Question 20

Which of the following is not a strength member used in optical cable?

A)steel wire
B)germanium
C)aramid yarns
D)glass elements

Question 21

When the stranding approach consists of individual elements (e.g. single-fiber or multi fiber loose tube buffer) than the cable is termed as

A)optical unit cable
B)coaxial cable
C)layer cable
D)bare glass cable

Question 22

The primary function of the structural member is load bearing.

Question 23

What is the Young's modulus of Kevlar, an aromatic polyester?

A)9 ×10¹⁰Nm^?2
B)10 ×10¹⁰Nm^?2
C)12 ×10¹⁰Nm^?2
D)13 ×10¹⁰Nm^?2

Question 24

The cable is normally covered with an outer plastic sheath to reduce _______________

A)abrasion
B)armor
C)friction
D)dispersion

Question 25

A measure of amount of optical fiber emitted from source that can be coupled into a fiber is termed as

A)radiance
B)angular power distribution
C)coupling efficiency
D)power-launching