Fiber Optic Dust Caps DON'T Protect Fiber Optic Connector Endfaces From Dust

What is the primary purpose of a fiber optic connector dust cap? To protect the connector endface from dust? No! In fact, a dust cap can actually introduce dust and other contaminants to the polished endface of a fiber optic connector.

Dust is everywhere. Smaller dust particles that have a diameter of 1um or less can remain suspended in air for very long periods of time, if not indefinitely. Dust can easily find its way into a dust cap, and stow away until it has the opportunity to jump aboard your fiber optic connector endface.

Even worse, dust caps often contain grease, gels or other compounds left over from when the dust cap was manufactured. For example, the plastic dust caps used on many fiber optic connectors may contain mold release residue. Even blasting air into the cap will not remove these tenacious compounds.

Unfortunately, many people believe that just because a fiber optic connector has a "dust cap" installed, it has been protected from contaminates and therefore does not need to be cleaned. As you now realize, nothing can be further from the truth. It is important to always clean a fiber optic connector endface immediately before mating it, regardless of whether or not it has been "protected" with a dust cap.

Your fiber optic system may contain the very best Corning fiber optics laser optimized for maximum performance. However, if you have dirty fiber optic connectors, you will experience sub-par performance. Proper connector cleaning is essential for the optimal maintenance of fiberoptic systems.

Why Use Fiber Optic Dust Caps?

Dust caps do a great job at protecting fiber optic connector endfaces from contact with objects that can scratch, chip, crack or otherwise physically damage the polished core of the fiber. Dust caps also provide ferrule protection and are ideal for protecting connectors from physical damage while in storage or in transit. If you accidentally drop a connector that's wearing a dust cap, chances are it will survive the fall. It advisable to install dust caps on any fiber optic connector that is not actively in use.

Dust caps can be purchased alone, and some fiber optic connectors come with protective caps already installed. Typically, the cap is a sleeve or boot that is closed at one end and which fits tightly over the ferrule of the fiber optic connector.

Which raises another issue. Before mating a fiber optic connector, don't just clean the endface. First, clean the body of the connector ferrule to remove any residual manufacturing compounds. Otherwise, the residue may cause the ferrule to bond permanently with the mating sleeve. This can make it impossible to avoid breaking the ferrule if there is any need to unmate the fiber optic connector.

In conclusion, the name "dust cap" is obviously a misnomer. A better term might be "protective cap." Old habits die hard, so it may be a long time before a new, more accurate phrase is adopted for popular use. In the meantime, just remain aware of what "dust caps" can and can't do in terms of protecting a fiber optic connector!

"Cheap Fiber Optic Patch Cords" - Beware of Knockoffs!

In recent years, there has been an influx of counterfeit fiber optic cables, connectors, pigtails and patchcords coming into the U.S. from China and other Asian nations. These bogus fiber optic cables may have a phony UL number, or they may purport to contain a name-brand fiber.

On the other hand, there are also authorized manufacturers and distributors in these very same nations that produce legitimate products. How do you tell if a particular fiber optic cable or patchcord is authentic?

Evaluating Fiber Optic Cable Distributors

When evaluating fiber optic cable and patchcords, there are several things you can do. For example, you may notice something odd about the Underwriters Laboratory (UL) number that's printed on the cable jacket (e.g. too many numbers, odd numbering sequence, etc.). If so, you can go to the UL website, www.ul.com. There you can click on "Online Certifications Directory," which will take you to a page where you can type in the cable's UL number. If the number is not recognized by UL, you can assume that your fiber optic product is counterfeit.

Even if the UL website shows that the number is registered to a legitimate company, this is no guarantee that the suspect company didn't copy it. To be certain, you can contact the registered firm to determine if the vendor who provided you with the fiber optic cable is one of their authorized distributors.

Another ploy of unscrupulous manufacturers is to print on the cable jacket the name of a leading optical fiber manufacturer. Again, if you suspect misrepresentation, you can contact that manufacturer to determine if the vendor is an authorized distributor. The manufacturer may request that you send a sample of the fiber optic cable so that they can examine it first-hand.

Also, be aware that counterfeit fiber optic cable may also have misrepresentations on the cable jacket as they apply to RoHS compliance, fire ratings, and so forth.

Fake Fiber Optic Connectors

As an example of how fast and loose some vendors are in terms of the products they sell, consider the recent experience of a leading fiber optics distributor. Upon receiving a product sample and price quote for fiber optic LC connectors from a vendor, the price seemed too good to be true. Suspicious, the distributor asked the vendor if the LC connectors were licensed, as is required by law. The vendor then replied, "Oh, you want the licensed version." He then produced a different sample, which he said was available at a higher price.

Fiber Optic Buyers Beware

As a fiber optic installer, the last thing you want to do is to purchase counterfeit fiber optic cable or pigtails from an unknown manufacturer. Joining optical fibers whose glass chemistry is even slightly different can:

• Make it difficult or impossible to get a clean fusion between the two optical fibers
• Create high back reflection and loss, due to an imperfect fiber optic splice
• Cause the fiber optic splice to fracture and fail after the installation is complete

Finally, inferior counterfeit products can erode confidence in the fiber optics industry as a whole. If you are offered questionable fiber optic products, you can report your suspicions to the National Intellectual Property Rights Coordination Center (IPR). This is a joint operation between U.S. Customs and the F.B.I. that is set up to combat the distribution of counterfeit goods. To contact the IPR, dial (202) 927-0810.