NAVEDTRA 14196A, NAVY ELECTRICITY AND ELECTRONICS SERIES MODULE 24-FIBER OPTICS Flashcards
What can be defined as a recurring disturbance advancing through space with or without the use of physical medium?
Wave motion
Who collected the four fundamental equations that completely describe the behavior of the electromagnetic fields?
James Clerk Maxwell
What are Quanta known as when referring to light energy?
Photons
What is the approximate speed of light?
186,000 miles per second
Which type of wave motion is represented by the motion of water?
Transverse-wave motion
Which type of substances transmit almost all the light waves falling upon them?
Transparent
Which type of substances either reflect or absorb all the light rays that fall upon them?
Opaque
What is the wave called that strikes a reflecting surface?
Incident
What are substances called through which some light rays can pass, but through which objects cannot be seen clearly because the rays are diffused?
Translucent
What is the imaginary line perpendicular to the point at which the incident wave strikes the reflecting surface called?
Normal
What is the angle between the incident wave and the normal called?
Angle of incidence
Which law states that “the angle of incidence is equal to the angle of reflection”?
Law of reflection
What is the angle called between the normal and the path of light wave through a second medium?
Angle of refraction
How many different methods are used to describe how light is transmitted along the optical fiber
2
What measures the speed of light in an optical medium?
Index of refraction
What is the index of refraction for glass?
1.50
What is the index of refraction for air?
1.00
Which law is used to describe the relationship between the incident and the refracted rays at the boundary?
Snell’s Law of Refraction
How many parts does the basic structure of an optical fiber consist of?
3
What is the layer of material called that surrounds the core in optical fiber?
Cladding
What is the layer of material called that surrounds the cladding in optical fiber?
Coating or Buffer
Which theory is used to approximate the light acceptance and guiding properties of optical fibers?
Ray
Which theory describes the behavior of light within an optical fiber?
Mode
How many different types of rays can propagate along an optical fiber?
2
Which type of rays pass through the axis of the optical fiber?
Meridional
Which type of rays travel through an optical fiber without passing through its axis?
Skew
Which classification of meridional rays remain in the core and propagate along the axis of the fiber?
Bound
What is a measurement of the ability of an optical fiber to capture light?
Numerical Aperture (NA)
What are the typical NA values for glass fibers?
0.20-0.29
Which type of wave is a wave whose surfaces of constant phase are infinite parallel planes normal to the direction of propagation?
Plane
What is an optical fiber that operates above the cutoff wavelength called?
Single mode fiber
What is an optical fiber that operates below the cutoff wavelength called?
Multimode fiber
What is a set of guided electromagnetic waves called in relation to optical fiber?
Modes
What is the exchange of power between two modes called?
Mode coupling
What determines how many modes a fiber can support?
Normalized frequency
How many types are optical fibers classified into?
2
Around how many micrometers (m) is the typical core size of single mode fibers?
8-10
What is the spreading of light as light propagates along a fiber called?
Dispersion
Over how many modes can be propagated by multimode fibers?
100
Which type of cable will support 125m links at 40 and 100 Gbit/s?
OM4
OM3 fibers provide sufficient bandwidth to support 10 Gigabit Ethernet up to how many meters?
300
OM4 fibers provide sufficient bandwidth to support 10 Gigabit Ethernet up to how many meters?
550
What is the maximum modulation rate of LEDs because they cannot be turned on/off fast enough to support higher bandwidth applications?
622 Mbit/s
Which jacket color is recommended for 50/125 um “Laser Optimized” OM3 and OM4 fiber?
Aqua
Which effect is caused by the different speeds of the individual modes in a light pulse?
Modal dispersion
What is an optical fiber which is made out of plastic?
Plastic Optical Fiber (POF)
What is the maximum distance of Hard Clad Silica (HCS) fibers?
2 kilometers
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?
Plastic Clad Silica (PCS)
What reduces the amount of optical power transmitted by the fiber?
Attenuation
What spreads the optical pulse as it travels along the fiber?
Dispersion
What is defined as the portion of attenuation resulting from the conversion of optical power into another form?
Absorption
Which type of absorption is caused by basic fiber-material properties?
Intrinsic
Which type of fibers are predominately used in fiber optics because of their low intrinsic material absorption at the wavelengths of operation?
Silica
In silica glass, the wavelengths of operation range from 700 nm to how many nm?
1600
Which type of absorption is caused by impurities introduced into their fiber material?
Extrinsic
Which type of losses are caused by the interaction of light with density fluctuations within a fiber?
Scattering
What is the main source of loss called in commercial fibers operating between 700nm and 1600nm wavelength?
Rayleigh scattering
What is scattering called if the size of the defect is greater than one-tenth of the wave length of light?
Mie scattering
What are small microscopic bends of the fiber axis that occur mainly when a fiber is cabled?
Microbends
What is the spreading of a pulse of light as it travels down the length of an optical fiber that limits the bandwidth
Dispersion
How many different types of dispersion are there?
5
Modal dispersion only occurs in which type of fibers?
Multimode
Which type of dispersion occurs because different wavelengths (colors) also travel at different velocities through a fiber, even in the same mode?
Material
What specifies the range of wavelengths that can propagate in the fiber?
Spectral width
What is the spectral width of a laser diode?
.1nm-3nm
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?
Waveguide
Which type of fiber is waveguide dispersion the most significant?
Single-mode
Which term is given to the phenomenon by which different spectral components of a light pulse travel at distant speeds?
Chromatic Dispersion (CD)
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?
Transverse
