BICSI Installer 2 Fiber flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Decibel loss formula

Loss in decibels equals 10 times the base-10 logarithm of input power divided by output power; a 10 dB loss means one-tenth of the power remains.

dBm reference

Power in dBm equals 10 times the base-10 logarithm of power in milliwatts divided by one milliwatt; 0 dBm is 1 mW and -3 dBm is about 0.5 mW.

Single-mode core size

Single-mode fiber typically has an 8 to 10 micrometer core and carries 1310 and 1550 nanometer wavelengths, supporting long-reach and high-bandwidth transmission.

Multimode core sizes

Multimode fiber uses 50 or 62.5 micrometer cores and commonly operates at 850 and 1300 nanometers; modal dispersion limits distance compared with single-mode.

Numerical aperture

Numerical aperture equals the sine of the acceptance angle; a higher NA accepts more light but usually increases modal dispersion in multimode fiber.

Link loss budget

The loss budget is transmitter output power minus receiver sensitivity minus a safety margin; total cable, connector, and splice losses must not exceed it.

OM3 and OM4

OM3 and OM4 are laser-optimized 50-micrometer multimode fibers; OM4 has higher bandwidth and supports longer 10-gigabit and 40-gigabit distances.

Loose-tube cable

Loose-tube fiber cable places fibers in gel-filled tubes around a central strength member; it is suited to outside-plant and long outdoor runs.

Tight-buffered cable

Tight-buffered cable has a protective buffer directly on each fiber, making it flexible and suitable for indoor jumper and horizontal cabling.

APC connector angle

An APC connector has an 8-degree angled ferrule end face; it provides high return loss and must not be mated with a flat UPC connector.

Plenum cable rating

Plenum-rated fiber cable, marked OFNP or OFCP, has low smoke and flame spread for use in air-handling spaces such as return-air ceilings.

Connector ferrule sizes

SC, FC, and ST connectors use 2.5-millimeter ferrules, while LC connectors use 1.25-millimeter ferrules; ferrule size does not determine polish.

Pull tension limit

Premises fiber cable is commonly limited to about 25 pounds-force pulling tension, but the manufacturer's published limit always governs the installation.

Pull bend radius

During pulling, fiber cable typically needs a bend radius of at least 20 times its outside diameter; installed radius is often 10 times diameter.

Conduit fill rule

For three or more cables, conduit fill should not exceed 40 percent; one cable may use 53 percent and two cables 31 percent.

Strength member pulling

Pull on the cable strength member with a pulling eye or grip rather than the jacket, and use a swivel to prevent twisting.

Firestop penetration

Cable penetrations through rated walls or floors must be sealed with a listed firestop system tested to ASTM E814 or UL 1479.

Fusion splice loss

A properly made fusion splice typically adds 0.1 decibel or less; mechanical splices and connectors commonly add up to about 0.3 decibel.

Cleave angle limit

A fiber cleave for fusion splicing should be within about one degree of perpendicular and free of mist or hackle to produce a low-loss splice.

APC to UPC mating

Mating an angled APC connector to a flat UPC connector causes high loss and reflection because the end faces do not physically contact correctly.

Connector inspection zones

End-face inspection divides the ferrule into zones A through D; defects in the central core zone A are most critical for loss.

Splice loss OTDR gainer

An apparent negative splice loss, called a gainer, can result from backscatter differences; bidirectional OTDR averaging gives the true splice loss.

Tier 1 fiber test

Tier 1 testing uses an optical loss test set to measure insertion loss and length; Tier 2 adds an OTDR trace for troubleshooting and splice analysis.

Encircled flux launch

Encircled flux is a controlled multimode launch condition required for accurate loss testing; a mandrel wrap or mode conditioner helps achieve it.

OTDR dead zone

The OTDR event dead zone is the minimum spacing for resolving two reflective events; the attenuation dead zone is longer for resolving loss events.

OTDR distance measurement

An OTDR calculates distance from light round-trip time and the fiber's group index of refraction, so an incorrect index setting skews length.

Visual fault locator

A visual fault locator injects visible red light to reveal breaks, tight bends, and bad connectors near the tester through a glowing leak.

NEC Article 770

National Electrical Code Article 770 covers installation requirements for optical fiber cables and their associated boxes, raceways, and grounding.

TIA-606 labeling

TIA-606 provides administration standards for labeling and documenting telecommunications spaces, cables, and pathways so links can be traced.

Fiber scrap disposal

Fiber scraps and cleaved ends must go into a closed container, not trash or clothing, because they can penetrate skin and eyes.

Laser safety rule

Never look into a fiber end or connector unless the source is off and verified; infrared laser light is invisible and can damage the retina.

Test record contents

A fiber test record should include link identifier, date, tester and calibration, reference method, wavelengths, loss results, and pass-fail status.