ETA I EXAM SCRIPT WITH CORRECT
ANSWERS
◉ What type of light is used in fiber optic transmissions? Answer:
Infrared (IR)
◉ What are the four items needed for a fiber optic system to work?
Answer: Transmitter, fiber optic cable, receiver, and connector
◉ 1 mW is the same as what in dBm? Answer: 0 dBm (absolute
power)
◉ How is the power measured in fiber optics? Answer: dBm
◉ What fiber optic wavelength has the lowest loss? Answer: 1550
nm wavelength
◉ What wavelength windows are used most for fiber optic
communications? Answer: 850 nm, 1300 nm, and 1550 nm
wavelengths
◉ What year was fiber optic cable first used in commercial
telephone systems in the U.S.? Answer: 1977
, ◉ What light source is used for singlemode fiber? Answer: Laser
diode
◉ What two light sources are used with multimode fiber? Answer:
LED and VCSEL
◉ All wavelengths of light travel at the same speed. (true or false;
why) Answer: False; different wavelengths of light travel at different
velocities
◉ Which type of fiber has the larger core size: singlemode or
multimode? Answer: Multimode
◉ What is OSHA responsible for? Answer: OSHA is responsible for
enforcing it's standards on regulated entities
◉ What are two ways to reduce modal dispersion? Answer: Use a
smaller core; use graded-index fiber
◉ What happens to the wavelength in fiber when the number of
modes increase? Answer: The wavelength gets shorter with more
modes
ANSWERS
◉ What type of light is used in fiber optic transmissions? Answer:
Infrared (IR)
◉ What are the four items needed for a fiber optic system to work?
Answer: Transmitter, fiber optic cable, receiver, and connector
◉ 1 mW is the same as what in dBm? Answer: 0 dBm (absolute
power)
◉ How is the power measured in fiber optics? Answer: dBm
◉ What fiber optic wavelength has the lowest loss? Answer: 1550
nm wavelength
◉ What wavelength windows are used most for fiber optic
communications? Answer: 850 nm, 1300 nm, and 1550 nm
wavelengths
◉ What year was fiber optic cable first used in commercial
telephone systems in the U.S.? Answer: 1977
, ◉ What light source is used for singlemode fiber? Answer: Laser
diode
◉ What two light sources are used with multimode fiber? Answer:
LED and VCSEL
◉ All wavelengths of light travel at the same speed. (true or false;
why) Answer: False; different wavelengths of light travel at different
velocities
◉ Which type of fiber has the larger core size: singlemode or
multimode? Answer: Multimode
◉ What is OSHA responsible for? Answer: OSHA is responsible for
enforcing it's standards on regulated entities
◉ What are two ways to reduce modal dispersion? Answer: Use a
smaller core; use graded-index fiber
◉ What happens to the wavelength in fiber when the number of
modes increase? Answer: The wavelength gets shorter with more
modes
