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Encircled Flux (EF) test solutions

Key Features

EF-compliant as per TIA-526-14-C and IEC 61280-4-1 Ed. 2.0 at 50 µm,

 850/1300 nm guaranteed

Optimized for multimode loss testing

Tier-1/2 testing of multimode fibers as recommended in TIA-568

Reference-grade UPC connectors for maximum precision and repeatability Built-in-EF-compliant light source–no extra equipment to manipulate


Encircled Flux (EF) is a new standard that defines how to control the source launch conditions as specified in TIA-526-14-C and IEC 61280-4-1 Ed. 2.0.

Whether for an expanding enterprise business or a large-volume data center, the new high-speed data networks built with multimode fibers are running under tighter tolerances than ever before.

These multimode fibers are the trickiest links to test because the results depend greatly on each device’s output conditions.

Testing with different equipment often returns different test results, sometimes higher than the budget loss itself. This may mislead the technician or make it impossible to locate the fault, resulting in unsuccessful turn-ups or a longer network downtime. Now, cable installers can rely on their Tier-1 loss results and Tier-2 troubleshooting can be performed with maximum accuracy and utmost confidence of finding the actual problem. For more information, click here


Key Features

Up to three singlemode wavelengths

(1310 nm, 1550 nm, and 1490 nm or 1625 nm)

on a single port, or four wavelengths (850/1300 nm and 1310/1550 nm) on two ports

Three year warranty for low cost of ownership

Error-free, time-saving test features

Controlled multimode launching output

EF Ready: use with external launch mode conditioner for

EF-compliant multimode results


Automatic wavelength switching

Using the FLS-600 in Auto-Switching mode allows the unit to automatically toggle between available wavelengths. When using this source with a compatible power meter (FPM/FOT-600), the latter recognizes the wavelength in use and switches to the proper calibration parameter.

Distant referencing

Signal encrypting can also give the receiving-end information on the power to be used as reference, helping ensure efficient referencing, even when the two units are far apart.


EXFO’s FLS-600 allows for testing of passive optical networks (PONs) at 1310 nm, 1490 nm and 1550 nm, the three wavelengths recommended by the ITU-T (G.983.3) for PONs.


Key Features

Multifunctional light source: dual wavelength singlemode (1310/1550 nm),

Or four wavelengths (two multimode, and two singlemode) on two ports

Power autonomy of 120 hours

Highest output power in the industry

Three-year warranty and recommended calibration interval

Ergonomic, eye-catching handheld package



The FLS-300 light source can transmit with a wavelength-identification digital encrypted protocol, so that any compatible unit— the FPM-300 power meter and the FOT-300 optical loss test set—can automatically use the proper calibration parameters. This feature reduces the need for communication between the two technicians and decreases the potential for error.


Signal encrypting can also give the receiving end information on the power to be used as reference, helping ensure efficient referencing, even when the two units are far apart. For more information, click here


FLS-140 & FLS-240

Visual Fault Locator; VFL

The FLS’s is the easiest way to identify fibers from end to end and locate polished connector endfaces. Its red laser shines through most yellow-jacketed fibers to help you pinpoint breaks, bends, faulty connectors, splices and other causes of signal loss. It has a reach of up to 5 km a. The convenient FLS’s  locates faults visually by creating a bright red glow at the exact location of the fault on singlemode or multimode fibers.

Compact design and Cost-effective

With a pocket-size pen-style design, this visual fault locator can easily be carried anywhere. This long-lasting and lightweight tool is the complementary tool of choice for any fiber-testing field technician.

The FLS’s extremely high efficiency guarantees prolonged operation with two standard AAA alkaline batteries, typically providing 40 and 50 hours of uninterrupted operation.

Priced to accommodate the tightest budgets, the FLS-140 and FLS-240 is a truly affordable way to locate faults in OTDR dead zones.

Its effectiveness justifies purchasing one for just about every fiber technician.

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