CFOT - Certified Fiber Optic Technician Optical Fiber and Cable Types Questions and Answers

Question 1

An optical fiber is characterized by a small core diameter of approximately 9 µm, minimal signal attenuation over long distances, and the use of laser light sources.
Its performance is primarily limited by chromatic dispersion.
What type of fiber is this?

Accepted Answer

Singlemode (OS2)

Answer

Step-index multimode (OM1)

Answer

Graded-index multimode (OM3)

Answer

Plastic optical fiber (POF)

Question 2

A technician is installing an indoor, riser-rated cable for a 10 Gb/s multimode network. The cable jacket is aqua. According to the TIA-598C standard, which type of fiber is most likely inside this cable?

Accepted Answer

OM3 or OM4 Multimode

Answer

OS2 Singlemode

Answer

OM1 Multimode

Answer

OM5 Multimode

Question 3

Which of the following best describes the primary advantage of using bend-insensitive singlemode fiber (BIF) that complies with the ITU-T G.657 standard?

Accepted Answer

It minimizes signal loss (macrobending attenuation) when the fiber is installed in tight spaces with sharp bends.

Answer

It provides significantly higher data bandwidth than standard G.652D fiber.

Answer

It is more resistant to physical damage from crushing or impact forces.

Answer

It uses a plastic core, which makes it more flexible and less expensive than glass fiber.

Question 4

A network installation requires a fiber optic cable to be run in an underground duct between two buildings. The environment is subject to significant temperature fluctuations and potential moisture. Which cable construction is most suitable for this application?

Accepted Answer

Loose-tube gel-filled cable

Answer

Simplex patch cord

Answer

Tight-buffered indoor cable

Answer

Flat drop cable

Question 5

What are the standard core and cladding diameters for a typical OM3 or OM4 multimode optical fiber?

Accepted Answer

50/125 µm

Answer

9/125 µm

Answer

62.5/125 µm

Answer

8.3/125 µm

Question 6

In a fiber optic cable, what is the primary function of the aramid yarn (e.g., Kevlar®) component?

Accepted Answer

To absorb pulling forces during installation and provide tensile strength.

Answer

To provide electrical conductivity for cable locating.

Answer

To act as a water-blocking agent to protect from moisture.

Answer

To provide color coding for individual fiber identification.