NAVEDTRA 14196A, NAVY ELECTRICITY AND ELECTRONICS SERIES MODULE 24-FIBER OPTICS

Question 1

What can be defined as a recurring disturbance advancing through space with or without the use of physical medium?

Answer 1

Wave motion

Question 2

Who collected the four fundamental equations that completely describe the behavior of the electromagnetic fields?

Answer 2

James Clerk Maxwell

Question 3

What are Quanta known as when referring to light energy?

Answer 3

Photons

Question 4

What is the approximate speed of light?

Answer 4

186,000 miles per second

Question 5

Which type of wave motion is represented by the motion of water?

Answer 5

Transverse-wave motion

Question 6

Which type of substances transmit almost all the light waves falling upon them?

Answer 6

Transparent

Question 7

Which type of substances either reflect or absorb all the light rays that fall upon them?

Answer 7

Opaque

Question 8

What is the wave called that strikes a reflecting surface?

Answer 8

Incident

Question 9

What are substances called through which some light rays can pass, but through which objects cannot be seen clearly because the rays are diffused?

Answer 9

Translucent

Question 10

What is the imaginary line perpendicular to the point at which the incident wave strikes the reflecting surface called?

Answer 10

Normal

Question 11

What is the angle between the incident wave and the normal called?

Answer 11

Angle of incidence

Question 12

Which law states that “the angle of incidence is equal to the angle of reflection”?

Answer 12

Law of reflection

Question 13

What is the angle called between the normal and the path of light wave through a second medium?

Answer 13

Angle of refraction

Question 14

How many different methods are used to describe how light is transmitted along the optical fiber

Answer 14

2

Question 15

What measures the speed of light in an optical medium?

Answer 15

Index of refraction

Question 16

What is the index of refraction for glass?

Answer 16

1.50

Question 17

What is the index of refraction for air?

Answer 17

1.00

Question 18

Which law is used to describe the relationship between the incident and the refracted rays at the boundary?

Answer 18

Snell’s Law of Refraction

Question 19

How many parts does the basic structure of an optical fiber consist of?

Answer 19

3

Question 20

What is the layer of material called that surrounds the core in optical fiber?

Answer 20

Cladding

Question 21

What is the layer of material called that surrounds the cladding in optical fiber?

Answer 21

Coating or Buffer

Question 22

Which theory is used to approximate the light acceptance and guiding properties of optical fibers?

Answer 22

Ray

Question 23

Which theory describes the behavior of light within an optical fiber?

Answer 23

Mode

Question 24

How many different types of rays can propagate along an optical fiber?

Answer 24

2

Question 25

Which type of rays pass through the axis of the optical fiber?

Answer 25

Meridional

Question 26

Which type of rays travel through an optical fiber without passing through its axis?

Answer 26

Skew

Question 27

Which classification of meridional rays remain in the core and propagate along the axis of the fiber?

Answer 27

Bound

Question 28

What is a measurement of the ability of an optical fiber to capture light?

Answer 28

Numerical Aperture (NA)

Question 29

What are the typical NA values for glass fibers?

Answer 29

0.20-0.29

Question 30

Which type of wave is a wave whose surfaces of constant phase are infinite parallel planes normal to the direction of propagation?

Answer 30

Plane

Question 31

What is an optical fiber that operates above the cutoff wavelength called?

Answer 31

Single mode fiber

Question 32

What is an optical fiber that operates below the cutoff wavelength called?

Answer 32

Multimode fiber

Question 33

What is a set of guided electromagnetic waves called in relation to optical fiber?

Answer 33

Modes

Question 34

What is the exchange of power between two modes called?

Answer 34

Mode coupling

Question 35

What determines how many modes a fiber can support?

Answer 35

Normalized frequency

Question 36

How many types are optical fibers classified into?

Answer 36

2

Question 37

Around how many micrometers (m) is the typical core size of single mode fibers?

Answer 37

8-10

Question 38

What is the spreading of light as light propagates along a fiber called?

Answer 38

Dispersion

Question 39

Over how many modes can be propagated by multimode fibers?

Answer 39

100

Question 40

Which type of cable will support 125m links at 40 and 100 Gbit/s?

Answer 40

OM4

Question 41

OM3 fibers provide sufficient bandwidth to support 10 Gigabit Ethernet up to how many meters?

Answer 41

300

Question 42

OM4 fibers provide sufficient bandwidth to support 10 Gigabit Ethernet up to how many meters?

Answer 42

550

Question 43

What is the maximum modulation rate of LEDs because they cannot be turned on/off fast enough to support higher bandwidth applications?

Answer 43

622 Mbit/s

Question 44

Which jacket color is recommended for 50/125 um "Laser Optimized" OM3 and OM4 fiber?

Answer 44

Aqua

Question 45

Which effect is caused by the different speeds of the individual modes in a light pulse?

Answer 45

Modal dispersion

Question 46

What is an optical fiber which is made out of plastic?

Answer 46

Plastic Optical Fiber (POF)

Question 47

What is the maximum distance of Hard Clad Silica (HCS) fibers?

Answer 47

2 kilometers

Question 48

Which type of optical fiber has a silica based core and a plastic cladding and in general have significantly lower performance characteristics, higher transmission losses, and lower bandwidths than all glass fibers?

Answer 48

Plastic Clad Silica (PCS)

Question 49

What reduces the amount of optical power transmitted by the fiber?

Answer 49

Attenuation

Question 50

What spreads the optical pulse as it travels along the fiber?

Answer 50

Dispersion

Question 51

What is defined as the portion of attenuation resulting from the conversion of optical power into another form?

Answer 51

Absorption

Question 52

Which type of absorption is caused by basic fiber-material properties?

Answer 52

Intrinsic

Question 53

Which type of fibers are predominately used in fiber optics because of their low intrinsic material absorption at the wavelengths of operation?

Answer 53

Silica

Question 54

In silica glass, the wavelengths of operation range from 700 nm to how many nm?

Answer 54

1600

Question 55

Which type of absorption is caused by impurities introduced into their fiber material?

Answer 55

Extrinsic

Question 56

Which type of losses are caused by the interaction of light with density fluctuations within a fiber?

Answer 56

Scattering

Question 57

What is the main source of loss called in commercial fibers operating between 700nm and 1600nm wavelength?

Answer 57

Rayleigh scattering

Question 58

What is scattering called if the size of the defect is greater than one-tenth of the wave length of light?

Answer 58

Mie scattering

Question 59

What are small microscopic bends of the fiber axis that occur mainly when a fiber is cabled?

Answer 59

Microbends

Question 60

What is the spreading of a pulse of light as it travels down the length of an optical fiber that limits the bandwidth

Answer 60

Dispersion

Question 61

How many different types of dispersion are there?

Answer 61

5

Question 62

Modal dispersion only occurs in which type of fibers?

Answer 62

Multimode

Question 63

Which type of dispersion occurs because different wavelengths (colors) also travel at different velocities through a fiber, even in the same mode?

Answer 63

Material

Question 64

What specifies the range of wavelengths that can propagate in the fiber?

Answer 64

Spectral width

Question 65

What is the spectral width of a laser diode?

Answer 65

.1nm-3nm

Question 66

Which type of dispersion occurs because the mode propagation constant is a function of the size of the fiber's core relative to the wavelength of operation?

Answer 66

Waveguide

Question 67

Which type of fiber is waveguide dispersion the most significant?

Answer 67

Single-mode

Question 68

Which term is given to the phenomenon by which different spectral components of a light pulse travel at distant speeds?

Answer 68

Chromatic Dispersion (CD)

Question 69

Which type of wave motion describes the up and down wave motion that is at a right angle to the outward motion of the waves?

Answer 69

Transverse