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FIBER OPTICS
EXAM PREP
37
Other
Not Applicable
04/22/2015

Additional Other Flashcards

 


 

Cards

Term

Name the three main parts of a fiber-optic system.

Definition

 a. Transmitter
b. Fiber-optic Cable
c. Receiver

Term

Which of the following is the main purpose of the fiber?

Definition

b. To guide the light

Term

In the public telephone network which of the following represents the biggest growth in traffic.

Definition

c. The internet

Term

What is the main obstacle to overcome in achieving a low loss optical fiber?

Definition

a. Reducing the impurities in the cable.

Term

In the 1970s, the greatest interest in applying fiber optics came from which of the following industries:

Definition

a. Military /government

Term

Describe the frequency and wavelength of light in relation to radio frequencies

Definition

a. Light is electromagnetic energy with a higher frequency and shorter wavelength than

              radio waves.

Term

. What is the name given to a particle of light?

Definition

      a. A particle of light is called a photon

Term

. Sketch a light ray being refracted. Label the incident ray, the refracted ray, and the normal.

Definition
Term

. Sketch a light ray being reflected. Label the incident ray, the reflected ray, and the normal.

Definition
Term

If an incident ray passing from air into water has a 75° angle with respect to the normal, what  is the critical angle?

Definition

A. 0c= arcsin(1.0003/1.33) = 48.773° since the angel of incidence is greater than the critical angle the ray is reflected.

Term

What is the wavelength of a 300-MHz electromagnetic wave in free space? A 250-kHz wave? A 2-GHz wave?

Definition

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

Term

Define critical angle.

Definition

The angle of incidence that yields an angle of refraction of 90° is the critical angle.

Term

Does light travel faster in air or in glass?

Definition

a. Air (air=300,000 km/s glass=200,000km/s) see figure 4-5

Term

What are the two main parts of an optical fiber?

Definition

a. Core and Cladding

Term

What usually happens to the performance of a fiber if the core diameter is reduced? If it is enlarged?

Definition

Reduced better performance
              Enlarged= worse or decreased performance

Term

What is the path called that is followed by optical energy down a fiber?

Definition

It’s mode

Term

What is the name of a fiber that allows only one path for the light down the fiber?

Definition

Single mode fiber

Term

What is the name of a fiber with a core whose refractive index varies?

Definition

Graded index fiber

Term

Is the refractive index of the core higher or lower than that of the cladding?

Definition
HIGHER
Term

Modal dispersion is constant at all wavelengths.

 

Definition
FALSE
Term

One advantage of the graded-index fiber is that the wavelengths of low lo
and minimum dispersion always coincide.

Definition
FALSE
Term

Which type of dispersion does not exist in a single-mode fiber?

Definition

Model Disperation

Term

   Is the information-carrying capacity of a multimode fiber characterized by dispersion or by bandwidth?

Definition

Bandwidth

Term

  Is the information-carrying capacity of a single-mode fiber characterized by dispersion or by bandwidth?

Definition

Dispersion

Term

Name the two main mechanisms of attenuation in an optical fiber

Definition

Scattering and Absorption

Term

Is attenuation lower in a fiber at 850 nm, 1300 nm, or 1550 nm? Why?

Definition

1550 nm, as Rayleigh scattering decreases, wavelength increases

Term

For any particular single-mode fiber, what specific characteristic limits its data rate?

Definition

Material dispersion

Term

 Does an optical fiber recover from a short, intense exposure to nuclear radiation in seconds, minutes, hours, or days?

Definition

Seconds

Term

  The material NA of a fiber always indicates the modal conditions of light traveling within the fiber.

Definition
TRUE
Term

Name three materials commonly used as strength members

Definition

Kevlar, steel, and fiberglass

Term

Name two types of cable buffers

Definition

Loose or tight buffer

Term

Which is greater: installation load or operating load?

Definition

Installation load

Term

A main difference between an indoor cable and an outdoor cable is

Definition

A. Fiber bandwidth

B.  Ruggedness and durability

C. Number of fibers

D. Attenuation

Term

  What is the purpose of the source?

Definition

a.       Coverts electrical to optical

Term

Name the two main types of fiber-optic sources

Definition

LEDs and lasers

Term

 

List three packaging methods used to make coupling of light into a fiber more efficient?

Definition

 

 

a.       To micro lensed and pigtails

Term

What relationship between source NA and fiber NA results in NA mismatch loss?
NA mismatch loss?

Definition

a.       NA source > NA fiber

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