CFOT Fiber Optic Cleaning and Inspection 3

Question 1

What does the industry best practice principle 'inspect before you connect' require?

Accepted Answer

Visually inspect every connector end-face for contamination before mating

Answer

Always perform an insertion loss test before mating connectors

Answer

Verify connector polarity before making any connection

Answer

Check the fiber type label printed on the cable jacket before connecting

Question 2

Why must technicians never look directly into the end of an active fiber optic cable or connector?

Accepted Answer

Infrared laser light can cause permanent eye damage with no visible warning

Answer

Visible red light causes immediate eye strain and headaches

Answer

UV light in the fiber causes temporary flash blindness

Answer

Blue light frequencies gradually damage photoreceptors over time

Question 3

What does a reel-type cassette cleaner use to clean fiber optic connector end-faces?

Accepted Answer

Pre-moistened and dry cleaning fabric that advances to a fresh section each use

Answer

IPA-soaked felt rollers that spin against the ferrule

Answer

Micro-abrasive polishing film on a rotating drum

Answer

Statically charged plastic film that attracts particles

Question 4

What end-face geometry parameters measured by an interferometer directly affect connector return loss performance?

Accepted Answer

Fiber height (protrusion or undercut) and radius of curvature

Answer

Core eccentricity and cladding non-circularity

Answer

Cladding diameter and coating thickness

Answer

Numerical aperture and mode field diameter

Question 5

When inspecting a fiber end-face under a microscope, what appearance distinguishes a scratch from surface contamination?

Accepted Answer

Scratches appear as linear marks that persist after thorough cleaning attempts

Answer

Scratches appear as bright circular spots that disappear after cleaning

Answer

Scratches appear as dark circular pits only visible at 800x magnification

Answer

Scratches glow under the inspection scope's illumination source

Question 6

How often should fiber optic connectors be inspected and cleaned in an active network?

Accepted Answer

Every time they are disconnected and before every reconnection

Answer

Only during the initial installation procedure

Answer

Once a year during scheduled preventive maintenance

Answer

Only when excessive signal loss or errors are detected

Question 7

Why can even sub-micron particles cause measurable insertion loss on a single-mode fiber connector end-face?

Accepted Answer

The single-mode core is only ~9 μm, so even tiny particles block a significant portion of the light path

Answer

Sub-micron particles increase surface reflectivity across the entire end-face

Answer

Sub-micron particles permanently etch the glass through chemical reaction

Answer

Particles larger than the cladding are the only ones that cause damage