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Term
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If an incident ray passing from air into water has a 75° angle with respect to the normal, what is the critical angle? |
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Definition
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A. 0c= arcsin(1.0003/1.33) = 48.773° since the angel of incidence is greater than the critical angle the ray is reflected. |
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Term
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What is the wavelength of a 300-MHz electromagnetic wave in free space? A 250-kHz wave? A 2-GHz wave?
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Definition
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a. fc=v/f 300,000 km/s 300MHz = lm/s
b. JL=v/f 300,000 km/s 250kHz = l,200m/s
c. Jl=v/f 300,000 km/s 2GHz (109)=150mm/s |
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Term
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Definition
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The angle of incidence that yields an angle of refraction of 90° is the critical angle. |
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Term
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Does light travel faster in air or in glass?
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Definition
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a. Air (air=300,000 km/s glass=200,000km/s) see figure 4-5 |
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Term
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What are the two main parts of an optical fiber? |
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Definition
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Term
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What usually happens to the performance of a fiber if the core diameter is reduced? If it is enlarged?
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Definition
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Reduced better performance
Enlarged= worse or decreased performance |
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Term
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What is the path called that is followed by optical energy down a fiber? |
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Definition
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Term
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What is the name of a fiber that allows only one path for the light down the fiber? |
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Definition
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Term
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What is the name of a fiber with a core whose refractive index varies? |
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Definition
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Term
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Is the refractive index of the core higher or lower than that of the cladding? |
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Definition
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Term
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Modal dispersion is constant at all wavelengths.
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Definition
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Term
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One advantage of the graded-index fiber is that the wavelengths of low lo
and minimum dispersion always coincide. |
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Definition
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Term
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Which type of dispersion does not exist in a single-mode fiber? |
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Definition
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Term
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Is the information-carrying capacity of a multimode fiber characterized by dispersion or by bandwidth? |
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Definition
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Term
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Is the information-carrying capacity of a single-mode fiber characterized by dispersion or by bandwidth? |
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Definition
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Term
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Name the two main mechanisms of attenuation in an optical fiber |
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Definition
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Scattering and Absorption |
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Term
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Is attenuation lower in a fiber at 850 nm, 1300 nm, or 1550 nm? Why? |
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Definition
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1550 nm, as Rayleigh scattering decreases, wavelength increases |
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Term
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For any particular single-mode fiber, what specific characteristic limits its data rate? |
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Definition
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Term
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Does an optical fiber recover from a short, intense exposure to nuclear radiation in seconds, minutes, hours, or days? |
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Definition
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Term
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The material NA of a fiber always indicates the modal conditions of light traveling within the fiber. |
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Definition
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Term
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Name three materials commonly used as strength members |
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Definition
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Kevlar, steel, and fiberglass |
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Term
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Name two types of cable buffers |
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Definition
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Term
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Which is greater: installation load or operating load? |
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Definition
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Term
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A main difference between an indoor cable and an outdoor cable is |
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Definition
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A. Fiber bandwidth
B. Ruggedness and durability
C. Number of fibers
D. Attenuation |
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Term
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What is the purpose of the source? |
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Definition
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a. Coverts electrical to optical |
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Term
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Name the two main types of fiber-optic sources |
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Definition
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Term
List three packaging methods used to make coupling of light into a fiber more efficient? |
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Definition
a. To micro lensed and pigtails |
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Term
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What relationship between source NA and fiber NA results in NA mismatch loss?
NA mismatch loss? |
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Definition
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