>> What is a fiber optic cable tester?

A fiber optic cable tester is a hand-held troubleshooting device that sends red light from a semiconductor laser (635nm) down a fiber to check for faults such as cracked fibers or defective splices.

The visible red light travels along the fiber core until it reaches a fault, where it leaks out of the fiber. Light leaking through the fault can be seen through plastic coatings and jackets under suitable illumination. Infrared light in the signal leaks out at the same point, but your eyes cannot see it. The tester emits Class II red laser beam, making the light escaping from the damaged fiber easily visible from a distance.

Attenuation of glass fibers is much higher at 630 to 670nm wavelengths of red light than in the 1300 to 1650nm transmission window, but the red light can still travel up to 5km through standard fibers. Note that the fibers must be exposed to use fiber optic cable tester effectively. If the red light leaks out inside a thick cable wrapped in black plastic, you can’t see it.

This technique is particularly valuable in equipment bays and other places inside buildings where fibers are exposed.

Shining a flashlight beam down a multimode fiber can serve the same function, and has long been used to trace fiber continuity as well. However, the flashlight couples little light into a single mode fiber.

Whether installing or troubleshooting, the fiber optic cable tester is an essential tool that quickly and easily locates problem areas in fiber cables. By pinpointing the exact location of fiber damage, technicians can diagnose, troubleshoot, and fix the problem effectively. The cable tester is also used for conducting continuity tests and performing fiber identification.

The Continuous/Flash control button lets operators choose between continuous or flashing illumination.

>> Applications

Fiber optic cable tester can be used to locate sharp bends, breaks, and damages in fiber. It can also conduct end-to-end continuity tests. The other function is to perform fiber tracing and identification.

>> What types of tester are available?

There are two unique versions of fiber cable tester that are ergonomically designed for comfortable handling and portability. Both versions are equipped with a 2.5mm interface and are compatible with connectors such as SC, ST, and FC, while the 1.25mm adapter enables connection to LC and MU connectors.

To ensure ruggedness, it features rubber seals, a fully enclosed laser head and a long-lasting On/Off switch. It has been tested to provide reliable operation under intensive use and harsh conditions.

>> How do I use the fiber cable tester?

1. After connecting the tester to the connector ferrule (with the included patch cord), turn the tester “on”. Notice the red glow in the connector ferrule. While carefully inserting the cleaved field fiber into the connector using constant light pressure, notice the red glow diminish as the cleaved field fiber approaches the pre-polished fiber stub in the connector. The insertion mark on the fiber will also approach the end of the connector ferrule.

The red laser light from the tester will continue to radiate from the end of the pre-polished fiber stub until optimum contact is made between the cleaved field fiber and the pre-polished fiber stub in the connector. As the field fiber approaches the pre-polished fiber stub, less red laser light radiates from the end of the pre-polished fiber stub as it begins to continue through the field fiber.

2. When the cleaved field fiber stops solidly against the pre-polished fiber, the red glow will diminish until it is barely noticeable or disappears. The insertion mark should be even with the back edge of the connector ferrule. Continue to maintain light pressure until a slight bow forms in the fiber to maintain contact between the cleaved field fiber and the pre-polished fiber stub. Crimp the connector one time. The red glow should remain diminished (barely noticeable) after crimping the connector.

>> How do I maintain the cable tester?

1. To turn on the tester, press and hold the ON/OFF button for approx. 2-3 seconds. The green LED will illuminate to indicate that the unit is on. The green LED will link if the batteries require replacing.

2. To toggle between continuous and pulsed modes, use the 2Hz button. In continuous mode, the red LED will be off and in the 2Hz mode the red LED will be on.

3. Always clean the ST connector on the fiber jumper cable before connecting to the tester.

4. Never rotate the cable tester when mated to the jumper cable or another connector. This will cause damage to the tester and the connector.

5. Always replace the connector dust cap and switch the unit off after use.

Author Bio: Colin Yao is an expert on fiber optic communication technology and products. Learn more about fiber optic cable tester and fiber identifier on Fiber Optics For Sale Co. web site.

Category: Computers and Technology
Keywords: fiber optic cable tester