Fiber Optic Inspection Tutorial
Fiber Optic Inspection Tutorial
Fiber optic connectors are common throughout the network and give us the power to add, drop, move and change the network. However, it is an undeniable fact that the end surface contamination of fiber optic connectors is a major cause of network outages and downtime. This is why we always emphasize that cleaning of fiber optic connector end surface is very necessary. To inspect the end surface of connector ferrules is used to find dirt or scratches on fiber optic connectors and inspect polish-type connectors during the termination process. Fiber optic inspection plays a very important role in fiber optic termination. It is recommended that we should develop a habit of inspecting before we connect the fiber in order to ensure fiber end faces are clean prior to mating connectors. This tutorial mainly introduces the fiber optic inspection.
Knowledge About Fiber Optic Connector & End Surface Contamination
Fiber optic connectors are widely known as the most important part but the weakest and most problematic points in the fiber network. Before introducing fiber optic inspection, it is necessary to introduce some knowledge about fiber optic connectors and end surface contamination.
A fiber optic connector terminates the end of an optical fiber, and enables quicker connection and disconnection than splicing. The connector mechanically couples and aligns the cores of fibers so light can pass. A better connector loses very little light due to reflection or misalignment of the fibers. At present, more than 100 fiber optic connectors, including simplex and multi‐fiber connectors have been introduced to the market for a variety of applications.
There are 3 basic principles that are critical to achieving an efficient fiber optic connection perfect core alignment, physical contact and pristine connector interface. Today’s connector design and production techniques have eliminated most of the challenges to achieving core alignment and physical contact. What remains challenging is maintaining a pristine connector end surface. As a result, contamination is the No.1 source of troubleshooting in fiber networks. A fiber or connector end face should be free of any contamination or defects, as shown in Figure 1. Common types of contamination and defects include dirt, oil, pits and chips as well as scratches (Figure 2). Inspection of the end surface of a connector is one of the best ways to determine the quality of the termination and diagnose problems like dirt on the connector or scratches. In addition, there are a number of different sources, such as test equipment, dust caps, bulkheads, people and environment, where dirt and other particles can contaminate the fiber and connector end surface. Fiber optic connectors and ports on test equipment are mated frequently and are highly likely to become contaminated. Once contaminated, this equipment will often cross-contaminate the network connectors and ports being tested. Thus, inspecting and cleaning test ports and leads before testing network connectors prevents cross-contamination.
Figure 2. Common types of contamination and defects
Fiber Optic Inspection
Fiber optic inspection is suggested to carry out before mating connectors. As Figure 3 shown, we must inspect and ensure the end surface is clean. If it is not clean, a cleaning process must be carried out. Fiber optic inspection and cleaning are simple steps with immense benefits. As fiber optic cleaning has already been written a lot, then we will mainly introduce the fiber optic inspection of connectors in the following contents.
Figure 3. "Inspect Before You Connect" process
Tools for Fiber Optic Inspection
In fact, fiber optic inspection includes visual inspection and inspection by fiber optic inspection equipment. It is generally done with the use of fiber optic inspection microscopes in order to view the end surface. A fiber optic inspection microscopes is a customized microscope used in order to inspect optical fiber components. The fiber optic inspection microscopes should provide at least 200 times total magnification. Specific adapters are needed to properly inspect the end serface of most connector types, for example: 1.25 mm, 2.5 mm, or APC connectors. Generally speaking, the tools used for fiber optic inspection include:
Clean, resealable container for the endcaps Fiber optic inspection microscopes Bulkhead probe
Fiber optic inspection microscopes come in many varieties starting with simple inexpensive portable microscopes generally made by modifying simple optical microscopes to hold the connector being inspected. Nowadays, the most commonly used types of fiber optic inspection microscopes are video fiber optic microscope (desktop) and handheld fiber optic microscope. (See Figure 4.)
Figure 4. Video fiber optic microscope (desktop) and Handheld fiber optic microscope
The bulkhead probe is a handheld fiberscope used in order to inspect connectors in a bulkhead, backplane, or receptacle port. It should provide at least 200x total magnification displayed on a video monitor. Handheld portable monitors are also available. Specific adapters are needed in order to properly inspect the end surface of most connector types.
Fiber Optic Connector Inspection Steps
Make sure that the lasers are turned off before you begin the inspection.
Warning: Invisible laser radiation might be emitted from disconnected fibers or connectors. Do not stare into beams or view directly with optical instruments. Remove the protective cap and store it in a clean resealable container. Verify the style of connector you inspect and put the appropriate inspection adapter or probe on your equipment. Insert the fiber connector into the fiber optic microscope adapter, and adjust the focus ring so that you see a clear end surface image as Figure 5 shows. Or, place the tip of the handheld probe into the bulkhead connector and adjust the focus as Figure 5.
On the video monitor, verify that there is no contamination present on the connector end surface. Here you can the sample images of contamination conditions in Figure 6.
If the end surface is not clean, to clean the end surface and reinspect. Immediately plug the clean connector into the mating clean connector in order to reduce the risk of recontamination.
Fiber optic connectors are valuable and essential in fiber networks, but they must be handled properly. In order to ensure the fiber connection work with high performance, to keep fiber and connectors end surface clean is very necessary. This can be easily achieved with proactive inspection and cleaning. For inspection, we must use a proper inspection tools and strictly observe the each steps of inspection. If the inspection result shows that end surface is not clean, a cleaning process must be carried out for the end surface. Of cause, a connector end surface will suffer permanent damage after mating or numerous cleanings. At this time, it should be replaced by a new one.
Fiber-Mart Fiber Optic Inspection and Cleaning Solution
Fiber-Mart offers a comprehensive line of fiber optic inspection and cleaning products which help you to complete your fiber optic termination efficiently. For fiber optic inspection tools, Fiber-Mart provides a variety of cost-effective fiber inspection tools which are of good quality and endurable, such as handheld microscope, video microscope, etc. For fiber optic cleaning, many kinds of fiber optic cleaning products such as pen shape cleaner, reel connector cleaner, cleaner replacement tape, connector cleaning swabs as well as other cleaning accesories which are used to ease or remove all kind of dirty particles, such as dust, dripping, moist. For more information, please contact us over [email protected]
Email for Technical Tips
-consulting for technical supports or relevent product buying guide
Email for [email protected]
News for Wednesday 20 May, 2015