Electronic Communication by Gary Miller Chapter 17 with Answers

Chapter 17 Fiber Optics

1	Which is an advantage of optical communication links over using transmission lines or waveguides?
	a. Small size
	b. Extremely wide bandwidths
	c. Immunity to electromagnetic interference (EMI)
	d. Lower cost
	e. All the above
2	The most common light used in fiber-optic links is
	a. Infra-red
	b. Red
	c. Violet
	d. Ultraviolet
3	The optical band designation(s) include
	a. S
	b. C
	c. L
	d. a and b above
	e. All the above
4	In the telecommunications industry, the most commonly used fiber(s) are
	a. 50 micron
	b. 62.5 micron
	c. 50 and 62.5 micron
	d. 125 micron
5	The abrupt change in refractive index from core to cladding of fiber-optic cable is called the
	a. Total internal reflection
	b. Numerical aperture
	c. Dispersion
	d. Step index
6	A technique that is used to minimize the pulse dispersion effect is to
	a. Use a higher frequency light source
	b. Use plastic cladding
	c. Minimize the core diameter
	d. All the above
7	The loss (attenuation) of signal in optical fiber is due to
	a. Scattering
	b. Absorption
	c. Macrobending
	d. Microbending
	e. All the above
8	Calculate the optical power 100 km from a 0.5 mW source on a single mode fiber that has 0.10 dB per km loss.
	a. 50 nW
	b. 500 nW
	c. 5 uW
	d. 50 uW
9	Which is not an important characteristic of a light detector?
	a. Responsitivity
	b. Dark current
	c. Power consumption
	d. Response speed
	e. Spectral respons
10	The dispersion in fiber optics is termed
	a. Modal
	b. Chromatic
	c. Polarization mode
	d. All the above
	e. a and b above
11	Fiber optic connections suffer high loss due to
	a. Air gaps
	b. Rough surfaces
	c. Axial misalignment
	d. Angular misalignment
	e. All the above
12	Fiber optic technology is used in applications of
	a. Local area networks (LANs)
	b. Cable TV (CATV) systems
	c. Telephone networks
	d. All the above
13	The dispersion of light in fiber-optic cable caused by a portion of the light energy traveling in the cladding is called
	a. Modal dispersion
	b. Material dispersion
	c. Waveguide dispersion
	d. Cable dispersion
14	Recent laser developments for fiber optic communication include
	a. Distributed feedback (DFB)
	b. Heterojunction
	c. Vertical cavity surface emitting (VCSEL)
	d. a and b above
	e. a and c above
15	The following consideration is important when deciding between using a diode laser or an LED
	a. Response time
	b. Power levels
	c. Temperature sensitivity
	d. Failure characteristics
	e. All the above

Answers:

E

A

E

C

D

C

E

D

C

D

E

D

C

E

A