Chapter 3 - Theory Flashcards

(28 cards)

1
Q

Fiber with a ______ numerical aperture have a _________ bandwidth capability due to greater pulse spreading. Called modal dispersion.

A

Large; smaller

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2
Q

The bending of a beam of light in transmission between two dissimilar lights.

A

Refraction

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3
Q

Index of refraction

A

1.471 (miles and kilometers per second)

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4
Q

When a light beam changes direction at an interface, between two dissimilar media and reflects back into the medium from which it originated.

A

Fresnel Reflection

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5
Q

The sum of all reflections in a fiber span, including all component reflections and the Rayleigh backscatter of the optical fiber.

A

Optical Return Loss

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6
Q

Reflectance and ORL are expressed in

A

dB

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7
Q

Fiber optics typically uses wavelengths that are transmitted from which wavelength range?

A

770 nm to 1675 nm wavelength

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8
Q

Nanometers most commonly used in fiber optics?

A

850, 1300, 1310, 1550, 1625

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9
Q

Are infrared regions visible to the human eye?

A

Yes

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10
Q

The _____________ is different at each wavelength.

A

Speed of light

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11
Q

Loss of signal power

A

Attenuation

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12
Q

Core and cladding ovality is ____________

A

Fiber Geometry

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13
Q

When transmission loss increases because the fiber radius has decreased to the point that light rays begin to pass through the cladding boundary.

A

Macrobending

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14
Q

Manufactured using existing G.652 fiber specifications and are ideal for fiber to the building.

A

Bend-insensitive single-mode fibers

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15
Q

Lowest losses and reflections are created by having the fibers in contact or near contact.

A

End Separation

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16
Q

What does VCSEL Source stand for?

A

Vertical-cavity surface - emitting laser as source

17
Q

What fiber is constructed with a core that has hundreds of concentric layers of glass between the center of the core and the cladding?

A

Graded-index Lightwave Propagation Multimode Fiber

18
Q

What is Chromatic dispersion?

A

Different wavelengths travel at different speeds, leading to unequal amounts of bending.

19
Q

What is a multimode issue that limits bandwidth?

A

Modal dispersion

20
Q

What does the number of modes in a fiber do as the wavelengths decrease?

A

The number of modes increases

21
Q

The _________ the fiber’s numerical aperture, the greater the effect of DMD.

22
Q

Which wavelength has the lowest attenuation?

23
Q

What part of the electromagnetic spectrum is used by fiber optic systems?

A

Infrared Light Region

24
Q

What is the bending of light called?

25
What type of reflection is caused by an air gap in the connector pair?
Fresnel
26
What are three ways to reduce modal dispersion in a multimode system?
LED, VCSEL, Graded-index fiber
27
True or False: All wavelengths travel at the same speed through the fiber.
False
28
What type of dispersion effects multimode fiber and is a direct relation to the larger core size?
Modal dispersion