Cleerline Technology Group

Ensuring a Successful Fiber Optic Network

Choosing Fiber Optic Tools for Verification, Inspection, and Testing

June 30, 2021 -The most important part of your fiber installation is that it works.  Our fiber is designed to be easier to use and install, but problems can still occur.  Alternatively, your installation may require certification details or other specific information.  We have fiber optic tools available to help you inspect, verify, or certify your cabling and connectors.  What are the differences, and which do you need?

Visual Fault Locators

Visual Fault Locators (VFLs) resemble flashlights.  To use, connect your fiber connector (our VFLs accept SC by default or LC with an adapter) and switch on the VFL.  Using an LED or similar light source, the VFL will send light down the fiber.

The difference with VFLs, as opposed to other fiber optic tools, is that the light is in a visible wavelength.  Frequently, red LEDs are used in VFLs, so to identify issues you simply need to look for red light leaking out of your cable.  If there are no major breaks or problems, you will be able to see red light exiting the end of the cable opposite the VFL.

VFLs are a great, basic tool to ensure that your fiber is inserted into the connector correctly. That’s why we use them during our termination process.  They are also very helpful for finding major issues.

However, VFLs will not give you any data on insertion loss. It is possible for high insertion loss to cause signal failure even though visible light is passing all the way through the fiber.  Similarly, a damaged or dirty connector may still pass light via VFL, but not allow correct signal transmission.

A Note on Eye Safety:

Warning: SFPs, testing equipment, and other functional fiber transmitters and receivers operate at a wavelength of light that is not visible to the human eye, but can still be harmful.  Never look into the fiber ports of any such device when plugged in, as this may cause damage to your eyes without you realizing it.

Inspection Tools

As we noted above, damaged or contaminated connectors can cause nonfunctional signal.  A VFL may help show issues around a connector, but it cannot indicate if a connector needs to be cleaned or replaced.  A fiber optic inspection microscope will, however, literally let you focus in on your connectors.  With either a handheld or video microscope, you can view any dust or scratches on the connector ferrule. This information will allow you to either clean or replace the connector.

Fiber optic microscopes designed for connectors will not, however, give you any data on your actual cable.

Testing Tools

Unlike VFLs or connector inspection scopes, fiber optic testing kits are designed to provide hard data on insertion loss.  Our Optical Light Source and Power Meter kits use non-visible wavelengths of light to measure loss in decibels (dB). For more information on testing procedures, view our article on the subject.

Data from testing kits can be used to troubleshoot your network or (depending on the test kit model), certify the network. They provide the highest level of detail out of our available tools.

Again, though, unlike a VFL, our testing kits will not visually show you the location of breaks. They also will not show contamination on connectors.  In fact, inspecting and cleaning connectors before testing is recommended to get accurate results.

What Do You Need?

VFLs, microscopes, and testing kits work all work together to help ensure network success.  Ideally, we recommend having all of these items on hand.

However, we understand that budgets can be limited, and project sizes can vary. Given this, we recommend the following. Please contact us if you have specific questions on an installation.

At Minimum, You Need a VFL + Basic Cleaning Supplies

At the absolute minimum, you need to have a VFL.  That’s why we include them in all of our termination kits.  Without a VFL, it’s almost impossible to verify that your fiber has been inserted into the connector correctly. Having a VFL will help to avoid problems that stem purely from incorrect termination.

At a basic level, we also recommend picking up either a Cleaning Kit or some One-Click Type cleaners.  Even if you can’t inspect the ferrule, you should be cleaning your connectors prior to use.  This will help avoid issues caused simply by dust.

Level Up: VFL + Testing Kit + Cleaning

Doing more fiber installations? You will need to be able to provide certification information and locate specific issues.  We recommend adding a certification-appropriate testing kit, like our SSF-TKITP-400, in addition to your VFL.  Having a testing kit will give you detailed information on insertion loss, helping to ensure installation success.

As noted above, also keep cleaning supplies on hand to avoid issues from contaminate on the connector ferrules.

Best of All Worlds: VFL + Testing Kit + Inspection + Cleaning

If you are installing high volumes of fiber and connectors, you need to take any guesswork out of the equation.  By adding fiber inspection tools and a testing kit to your arsenal, in addition to your VFL, you can clearly identify and solve problems before they occur. Especially if certifying installations, inspecting connectors prior to testing will help prevent re-tests due to dusty or scratched connectors, saving time.

Again, cleaning connectors is always vital to installation success, so ensure you always have cleaning supplies on hand.