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Note: The following technical article was current at the time it was published. However, due to changing technologies and standards updates, some of the information contained in this article may no longer be accurate or up to date.

Fiber Connector Termination Methods

In the early 80's, pioneers in the interconnection industry developed a basic method to attach a connector to a length of fiber optic cable. That method was the use of epoxy, applied onto the fiber with a cotton swab or toothpick. The coated fiber was inserted into the connector, the epoxy was cured, the fiber was cleaved, and finally a few polishing steps were performed to get the fiber smooth and flat (relative to the end of the connector). The time to do all that was 15 - 20 minutes per connector.

Similar methods are still being used today. The epoxies have been refined, the method of applying the epoxy has been facilitated, and the polishing films/tools optimized. In addition, many new connector designs and termination methods have been developed that enable a connector to be installed onto a fiber cable in less than two minutes!

In this article, we will examine several termination methods and the advantages/disadvantages of each.

First of all, the basic steps for using epoxy as a termination method are as follows (after the cable has been stripped down to the bare fiber):

  1. Mix the two components of the epoxy (resin and hardener). The epoxies these days have just the right viscosity to allow it to flow nicely between the very small space between the fiber and the connector ferrule hole and they also can be cured at various temperatures/times to enable excellent resistance to temperature extremes. Also, the mixing is made quite simple. Pre-measured packets are available that enable easy, no-mess mixing: just remove a clip and then mix the two components together by moving your fingers and thumbs around the external surface of the packet. Pre-mixed and pre-loaded epoxy is also available, in a syringe. This type of packaging requires that the pre-loaded syringes be kept frozen until ready for use, but the use of dry ice makes that relatively convenient and the advantages are that no mixing is required and the epoxy is devoid of air bubbles.

  2. Load the mixed epoxy into a syringe (unless it's pre-loaded of course).

  3. Inject the epoxy into the back end of the connector ferrule.

  4. Insert the prepared cable into the connector such that the bared fiber is inserted into the ferrule hole. Insert until the cable seats inside the connector. The fiber will be protruding out the front of the ferrule by typically ½ inch.

  5. Crimp: If the connector is being installed onto jacketed fiber, a crimping operation is required to retain the connector onto the cable strength members and jacket. This is usually accomplished via use of a crimp sleeve and, in order to retain the connector onto the cable's strength members as well as the jacket, two crimps are typically required.

  6. Install the connectorized cable into a curing holder (which serves to protect the protruding fiber from the damage that could occur from handling during the next step, curing the epoxy).

  7. Cure the epoxy: Place the connectorized cable & curing holder into an oven. There are curing ovens designed specifically for this purpose which are basically a hot plate with 12 - 20 holes in it which the connector/curing holder fits into. However, any kind of oven will work, as long as it is capable of achieving the proper temperature for the right amount of time. Hint: if a "conventional" oven is used, be sure to position the connector/curing adapter such that the mating end of the connector is facing the floor. This will avoid what is called "wicking", which refers to the flowing of epoxy out the back end of the connector and into the strength member strands (which can cause a brittle condition that will degrade the cable retention).

  8. Cleave the protruding fiber (using a pocket pen style scriber) as close to the ferrule tip as possible and remove this excess fiber with a straight, non-twisting pull.

  9. Dispose of the fiber by depositing it onto a piece of tape (regular masking tape works fine) or into a debris container that is set up for that purpose. This may seem overly cautious but if a piece of fiber gets stuck onto your finger or flies up into the air, it can end up in your skin or in your eye. See the "Ten Commandments for Fiber Safety" for additional information.

  10. Polish: This process is critical to optical performance& ..if a smooth finish is not achieved on the fiber, the light rays will be lose some power passing through the first connector and into the one mated to it. The first polishing step is intended to remove the excess epoxy from the ferrule tip via use of a relatively coarse grit polishing film. The subsequent polishing steps use increasingly finer grit films so as to gently create the desired smoothness on the fiber.

  11. Clean the ferrule tip/fiber. There are various methods of cleaning the polished ferrule tip. The method that gets the ferrule/fiber the cleanest is via use of a lint-free "wipe" that has been dipped into alcohol (use of 99% reagent-grade alcohol is recommended), followed immediately by a dry lint-free wipe, and finally to blow-dry using a can of clean, compressed air. The other methods are less effective but are generally sufficient (especially if the fiber is multimode, rather than singlemode):

    1. using the same alcohol-soaked wipe method as noted above but eliminating the blow-dry step is a good alternate;

    2. use of an available cleaning "box" that contains a special dry, lint-free cleaning tape on a reel is good, albeit expensive; 3- there's also an inexpensive sticky-tape product available that basically does the job; i.e., it generally produces sufficient cleanliness for multimode applications.

  12. Inspect: It is important to look at what has been accomplished during the polishing and cleaning steps. If the polishing was not done well (i.e., neither the ferrule nor the fiber were polished sufficiently smooth) and this connector was then mated to another, good connector, it is possible that the good connector could be damaged via the fiber being scratched by the "bad" connector. There are several microscopes available that make this inspection quite easy. They are designed to hold the connector in a position to enable simple focusing, and to magnify the polished ferrule tip sufficiently to enable seeing the ferrule tip and fiber well enough to be able to judge its quality (typically 100X; sometimes 200X).

  13. Test: Optical testing is the only way to assure that the quality of your terminated connector is good enough to transmit voice, data, or video signals without excessive degradation. For multimode, the only required test is Insertion Loss (a measure of how much light is passing through the connection). However, for singlemode, Return Loss must also be tested (a measure of how much light is being reflected as a result of the connection).

1) Heat-Cured Epoxy.

As the term implies, exposure to an elevated temperature cures the epoxy. The choice of epoxy is personal preference to a certain extent; however, it also depends on what kind of reliability is desired. For example, if the terminated connectors are never going to be exposed to temperature or humidity extremes beyond the typical variations expected when the thermostat is lowered to the night setting, there are several epoxies to choose from and they can be cured at a relatively low temperature without experiencing any problems.

However, what if the power is lost for several hours, or several days? If the installation is in Alaska, the connectors will obviously be exposed to some pretty cold temperatures. Or, at the other extreme, an installation in Tucson could get pretty warm if the power goes down due to an overload in August. And, a final example, Key West in the dead of summer. In a place like that, it not only gets warm, it gets humid.

To be optimally reliable, choose an epoxy and a cure temperature/time that yields a glass transition temperature (Tg) that is at least 10° C above the highest temperature that the connectors might be exposed to. In Alaska that high temperature is apt to not be very high; however, the higher the Tg, the better the resistance to cold temperatures as well. For example, curing Epoxy Technology. s EpoTek 353ND at 120° C for 30 minutes will enable passing the environmental requirements of Bellcore specification GR-326-CORE: Thermal Age (2 weeks @ 85° C), followed by Thermal Cycle (2 weeks @ -40° C to +75° C), followed by Humidity (2 weeks @ 90% RH, 75° C).

So, the advantage to the use of heat-cured epoxy is that you can achieve the optimal resistance to extreme environments. The disadvantages are that the time to terminate is long (typically 15 minutes), the time to cure is long (typically ½ hour), and you need an oven to do the curing.

2) Room Temperature-Cured Epoxy .

This epoxy is essentially the same as heat-cured epoxy, except for the fact that it cures at room temperature. That translates to an in-field termination being completed without the need for power. This is convenient, especially if the cabling is being installed at a new construction site where access to electricity is limited. However, there are some pitfalls associated with the use of this type of epoxy. The primary disadvantage is that the pot life is very short. Once the epoxy is mixed, only 10 connectors can typically be terminated before the epoxy starts to harden. Hence, the installer must work with small batches in pre-measured mixing packets, as previously described. But you have to work really fast to make effective use of the epoxy, even if you do utilize the packets. The other disadvantage is the relatively long cure time - you can. t start polishing until it cures and that takes 2 - 3 hours.

3) Pre-Injected Epoxy.

This method utilizes heat-cured epoxy but the connector manufacturer injects the epoxy, not the installer. Therefore, when the installer is ready to terminate, there is no epoxy, no mixing, no syringe, no injecting. To terminate this type of connector, one of the first steps is to apply heat to the connector in order to soften the epoxy (to enable the prepared cable to be inserted). To cure it, let it cool. The advantage: no epoxy injection. One of the disadvantages is that an oven is required to heat the epoxy and the connector housing becomes hot to the touch. Then, when the epoxy is sufficiently softened, the connector must be held by the installer in order to insert the cable. To do that, a special connector holder is needed. In addition, the heated epoxy has to cool to cure so, while it's cooling, a special cooling stand is needed. Another disadvantage is that the polishing generally takes longer due to the large "bubble" of epoxy that is formed at the tip of the connector ferrule after the epoxy is cooled. More epoxy means more polishing time.

4) UV Adhesive.

UV is an acronym for Ultra-Violet. This type of adhesive requires a UV light source for curing. It is a fast way to bond fiber to the connector ferrule. Also, the polishing process is easier compared to epoxy because the adhesive does not "puddle" on the ferrule tip as much as epoxy does. Therefore, there is less to remove during polishing. The downside of UV adhesive is that, in order to cure it, the UV light has to "see" the adhesive. Hence, a solid ceramic, stainless steel, or polymer ferrule cannot be used. A special ferrule with a glass capillary is required. The capillary is a glass rod at the center of the ferrule which includes a precision hole to accommodate the fiber. The UV light projects along the capillary to effect the fiber-to-ferrule bond. Advantages: It's fast (cure time is 45 seconds). Also, no curing oven is required. The disadvantages are:

  1. A UV light source is required (and it has to be capable of concentrating its light along the capillary)

  2. The connector requires a special ferrule with a glass capillary, and

  3. Resistance to environmental extremes (heat, cold, humidity) is significantly less than epoxy

The steps required to terminate a connector using this process are as follows:

  1. Squeeze about one drop of the adhesive into the back end of the connector

  2. Wait 2-3 seconds to allow the adhesive to draw into the glass capillary

  3. Insert the prepared cable into the connector

  4. Place the connector into the UV light fixture

  5. Cure by exposing the connector to the UV light for 45 seconds

  6. Crimp: If the connector is being installed onto jacketed fiber, two crimps are required to secure the strength members and jacket

  7. Cleave the protruding fiber

  8. Dispose of the cleaved fiber

  9. Polish

5) Cyanoacrylate Adhesive

The steps to use this adhesive system are as follows: Inject the adhesive, insert the prepared cable, and then spray the tip of the connector ferrule with an "accelerator" as a means of escalating the curing process. The curing time is fast (30 seconds-to-one minute). Also, the polishing process is quick (there is less material to remove from the ferrule tip, as compared to epoxy). In summary, the primary advantages are that it is fast and you don't need a curing oven. However, there are some disadvantages: it is too fast (i.e., the adhesive will harden before the fiber can be fully inserted into the ferrule) and, like UVadhesive, its resistance to environmental extremes is not as good epoxy.

The cyanoacrylate termination process is as follows:

  1. Install the connector onto the adhesive dispenser's tip so that the connector will form a seal (seal effectiveness is important - the fit can be deemed sufficient if the connector does not fall off when the dispenser is tipped upside down)

  2. With the dispenser tilted toward the floor, squeeze the dispenser so as to inject the adhesive into the connector. Keep squeezing until the adhesive is visible at the tip of the connector ferrule

  3. Remove the dispenser from the connector and wipe off the excess adhesive from the dispenser (note: after injecting, do not allow the connector to remain affixed to the dispenser for more than one minute, because the adhesive will harden)

  4. Cap the dispenser until ready for the next connector

  5. Insert the prepared cable

  6. Spray the accelerator onto the tip of the ferrule (note: hold the spray can about 6 inches from the connector and apply the accelerator down onto the ferrule tip, not from the side)

  7. Cure: once the accelerator is applied, wait for 30 seconds before proceeding to the next step

  8. Crimp: If the connector is being installed onto jacketed fiber, two crimps are required to secure the strength members and jacket

  9. Cleave the protruding fiber

  10. Dispose of the cleaved fiber

  11. Polish

6) Anaerobic Adhesive.

The basic premise of this adhesive system is to inject the adhesive, coat the bare fiber with a liquid activator, and then insert the cable. This is a similar process to cyanoacrylate except that instead of spraying an accelerator, you dip the fiber into a liquid "primer". The curing occurs as a result no air being present within the ferrule hole (hence the term anaerobic, or "absence of air"). The curing time is fast (30 seconds-to-one minute). This method has the same basic advantage as noted for the other adhesives; i.e., the polishing process is faster because there is less adhesive on the tip as compared to epoxy. So, the primary advantages are that it is fast and you don't need a curing oven or a UV light source. The disadvantages: it is too fast (the fiber can get locked up in the same manner as described above for the accelerator-cured cyanoacrylate adhesive) and, like both of the other adhesives, its resistance to environmental extremes is not as good as epoxy. In addition, the primer is solvent-based and readily evaporates if left exposed to air. Finally, a potentially expensive disadvantage is that some anaerobic adhesive/primer systems have a short, three month shelf life (other anaerobic plus the UV, cyanoacrylate, and epoxy systems typically have a 12 month shelf life).

The typical termination steps for an anaerobic adhesive system are as follows:

  1. Dip a brush into the primer or suck some primer into an all-plastic syringe (the primer is solvent-based and will chemically react with any sealing components made with rubber)

  2. Liberally apply some primer to a dry, lint-free wipe

  3. Rub the tip of the connector ferrule across the primer-soaked section of the wipe (so as to effect a "skin" of primer to seal off the ferrule hole)

  4. Squeeze (some systems utilize a squeeze bottle) or inject the adhesive into the back end of the connector until it is visible at the tip of the ferrule

  5. using the primer-soaked brush (or the primer syringe), apply the primer to the bared fiber (in order to reduce the potential of the cable locking up before it is fully inserted into the connector. Do not apply the primer to any other cable component, such as the buffer, strength members, or jacket)

  6. Insert the prepared cable into the connector (remember, it doesn't take long before the fiber will get stuck at a point prior to full insertion)

  7. Using the primer-soaked brush (or the primer syringe), apply primer to the ferrule tip. Be careful not to break the protruding fiber

  8. Using the edge of a dry wipe, "wick" away the excess primer from the tip of the ferrule ("wick away" translates to dabbing the still-liquid primer/adhesive such that the excess is removed)

  9. Cure: wait at least 30 seconds (one minute is advisable) before continuing on to the next step

  10. Cleave the protruding fiber

  11. Crimp: If the connector is being installed onto jacketed fiber, two crimps are required to secure the strength members and jacket
  12. Dispose of the cleaved fiber

  13. Polish

7) Acrylic Adhesive.

This is the newest adhesive system that is available. It is offered by The Siemon Company and is marketed under the name LightSpeed TM. One of the primary advantages is that the time to cure is just as fast as an anaerobic but it does not begin to harden immediately. The resultant benefit is that you have a full 30 seconds to get the fiber into the connector. So, "fiber-lock" will not occur. And, neither an oven nor a UV light source is required for curing. Another comparative benefit is that it resists exposure to environmental extremes significantly better than any of the other adhesive systems. Still another benefit is that this adhesive system uses an activator (or primer) in a similar manner as with an anaerobic; however, due to the differences in the material composition of both the adhesive and the activator, there are almost half as many steps required during the termination process (eight vs. fourteen). Another advantage is that the activator is not solvent-based and, consequently, will not evaporate when exposed to air. Finally, the shelf life is a full 12 months.

Because of the advantages noted, this adhesive system (compared to other adhesive and epoxy methods) offers the best combination of ease of use, termination speed, and environmental resistance.

Here are the eight easy steps required to terminate a connector using this adhesive system:

  1. Inject the adhesive into the back end of the connector using a factory-filled syringe

  2. Dip the prepared cable into the primer so that the bared fiber is covered as well as some portion of the buffer (it is acceptable to dip the strength members or jacket into the primer. Since it is not a solvent-based material, it has no affect on those cable components

  3. Insert the prepared cable into the connector. The installer doesn't have to feel rushed, he/she has a full 30 seconds to fully insert

  4. Cure: wait 30 seconds

  5. Crimp: If the connector is being installed onto jacketed fiber, two crimps are required to secure the strength members and jacket

  6. Cleave the protruding fiber

  7. Dispose of the cleaved fiber

  8. Polish







8) Crimp.

This kind of connector eliminates the use of epoxy/adhesive altogether. Such connectors utilize a method to mechanically grip the fiber and other cable components. Therefore, there is no need to inject/cure or even to soften/cool. Just insert the prepared cable and perform three crimps& .onto the fiber, the buffer, and the jacket.

The advantage is obvious& .no epoxy/adhesive to deal with; therefore, termination is easy and fast. One of the disadvantages, however is that the reliability over the long haul is questionable. Without an epoxy or adhesive to retain the fiber, there is less chance of being able to resist the effects of exposure to environmental extremes. Such effects as "pistoning" (movement of the fiber within the ferrule as a result of varying temperature/humidity) are apt to occur. However, the manufacturers have performed tests and claim that the crimping method retains the fiber sufficiently well to resist certain environmental extremes to such a degree that the Insertion Loss does not waver more than 0.2 dB. Note that such changes in loss are only relevant to before and after measurements; i.e., no loss measurements were reported during exposure to these environments. Another disadvantage is higher connector cost. In order to be able to retain the fiber via crimping, the connector design requires the use of more components and several of the components are more costly than those used for an epoxy/adhesive style connector. And, finally, the crimp mechanism is not capable of retaining and aligning singlemode fibers well enough to provide adequate optical performance. Hence, this type is only available for multimode cable.

The following are the seven steps to terminate a Crimp connector:

  1. Insert the prepared cable into the connector

  2. Crimp: If the connector is being installed onto jacketed fiber, two crimps are required to secure the strength members and jacket

  3. Place the connector into the fiber retention tool and activate the mechanism that causes the fiber to be secured

  4. Remove crimped connector from the tool

  5. Cleave the protruding fiber

  6. Dispose of the cleaved fiber

  7. Polish

9) No Epoxy/No Polish.

These special connectors include a short length of fiber that has been pre-epoxied to the connector ferrule and pre-polished at the factory. A fiber "stub" is left to protrude out the back of the ferrule. This stub is inserted into a splice mechanism that is pre-installed into the back end of the connector housing. This concept is based on the principle that the factory can do a better job epoxying and polishing than an installer can do in the field. The installer only has to prepare the cable, insert it into the connector, and crimp the back end. It is actually a little more involved than that. First of all, there is a special cleaver that you need so as to make sure that the length and the quality of the cleave is acceptable. Then there is a special installation tool to activate the fiber retention mechanism. The installation tool also includes a couple openings, one of which is used to crimp the rear of the housing so as to retain the buffer. The other opening is used to crimp down against a separate crimp sleeve in order to retain the cable's strength members and jacket. Note that it is suggested that a thin film of epoxy or adhesive be applied to the back end of the connector housing before the crimp sleeve is crimped in place so as to assure optimum retention of the connector onto the cable.

An installer who is experienced with this style of connector can terminate onto buffered fiber within 1-½ minutes. However, in comparison, the fastest epoxy/adhesive style (the acrylic LightSpeedTM adhesive) takes only 1-3/4 minutes to terminate when a similarly experienced person is performing the installation. Another advantage of the no epoxy/no polish style is, of course, that there's no need to deal with an epoxy/adhesive and no polishing is required. Hence, fewer consumables are required.

The only disadvantages are:

  1. special tools are needed (the cleaver and the installation tool)

  2. there are two fiber junctions occurring: one at the ferrule tip (as with any other connector style) and one within the splice mechanism (which translates to two places where an optical degradation can occur). And, if two such connectors are mated together within an adapter, the number of fiber junctions increases to three (vs. only one for all other termination methods)

  3. because of the splice junction, the long term reliability can be less than epoxy or some adhesive systems and

  4. higher connector cost (due to the additional components and operations required to epoxy and polish the fiber that is pre-installed at the factory)

The steps needed to terminate a connector using this method are as follows:

The first step in this process is to cleave the fiber. That sounds simple; however, there is a difference between this cleaving operation and the type needed with all of the other methods: the quality of the cleave is important because the cleaved fiber must butt up against the pre-installed fiber within the connector. Also the length is critical (a tolerance of +/- .005 inches is required). Therefore, the tool used for this operation is obviously important; i.e., an ordinary pocket scriber cannot be used. Instead, a cleaver that costs about four times more must be utilized (and each set of replacement blades cost approximately $60). Finally, this cleaving operation actually consists of seven sub-steps:

  1. Insert the prepared cable so that the end of the buffer is at the front edge of the appropriate mark on the cleaver (which will assure the proper fiber length)

  2. Release the retention clamp (which will hold the fiber in place)

  3. Actuate the scribing blades

  4. Bend the tail of the cleaver (to break away the excess fiber)

  5. Remove the cleaved fiber from the tool

  6. Dispose of the excess fiber

    The following eight steps will complete the termination:



  7. Insert the prepared cable into the connector (until it seats against the fiber stub)

  8. Inspect your handiwork thus far to make sure that there is a gap between the cable jacket and the rear of the connector. If there is no gap, pull the connector off of the fiber and start again

  9. If there is a gap, carefully install the connector into the installation tool

  10. Squeeze the installation tool until it closes and releases (the fiber is now held in place within the connector)

  11. Crimp the small portion at the back end of the connector (to retain the buffer) l) If jacketed cable is being used, it is recommended that epoxy or adhesive be applied to the strength members so as to optimize cable retention

  12. Crimp the crimp sleeve (to retain the strength members)

  13. Note that the crimp sleeve is not designed to be crimped a second time in order to retain the jacket. Since it is desirable to retain the jacket to the connector, slide the boot in place and then apply a small bead of epoxy or adhesive around the boot where the jacket enters it.

The following questions should be considered when choosing a fiber connector termination method:

  1. What kind of reliability is required (based on the environment in which the connector is to be installed)?

  2. What tools have to be purchased and how much do they cost?

  3. How much do the connectors cost?

  4. How much time and labor is required to terminate a typical connector?

  5. Consumables: Epoxy/adhesive, polishing film, cleaning materials (wipes, alcohol, etc.) will be consumed. How long do they last and how much does it cost to buy more?

Add it all up to establish a cost-per-termination. Compare the costs of at least two different methods and then consider the cost differential, the reliability, and the environmental compatibility.

Summary of the Pro's and Con's of Fiber Connector Termination Methods

Termination Method

Typical Time to Field Terminate onto Buffered Fiber (1)

(Minutes per Connector)

Time Allowed to Insert Cable

Source of Epoxy/Adhesive Cure

Heat-Cured Epoxy

10 + 30 (cure time)

2 hours

Oven

Room Temp-Cured Epoxy

10 + 120 (cure time)

15 minutes

Air

Pre-Injected Epoxy

8 + 30 (cool down time)

1 minute

Oven

UV Adhesive

5

30 seconds

UV Light

Cyanoacrylate Adhesive

3

< 5 seconds

Air

Anaerobic Adhesive

3

5 seconds

Activator

Acrylic (LightSpeed TM) Adhesive

2.5

30 seconds

Activator

Crimp

2

No limit

Not Applicable

No Epoxy/No Polish

1.5

No limit

Not Applicable


Termination Method

Relative Connector Cost

Special Tools Required (2)

Environmental Resistance

Heat-Cured Epoxy

Low

Curing oven

Excellent

Room Temp-Cured Epoxy

Low

None

Good

Pre-Injected Epoxy

Medium

Heating oven, cooling stand

Good

UV Adhesive

Medium

UV curing light

Fair

Cyanoacrylate Adhesive

Low

None

Fair

Anaerobic Adhesive

Low

None

Fair

Acrylic (LightSpeed TM) Adhesive

Low

None

Good

Crimp

High

Special installation tool

Fair

No Epoxy/No Polish

High

Special cleaver & crimp tool

 

(1) The time to field terminate as noted is based on use of manual polishing techniques (where applicable). If an Automated Field Polisher is used (such as Siemon part number FPOL) for the adhesive and crimp methods, 0.5 to 1.0 minute can be saved relative to the manual times noted above.

(2) The following tools are considered standard for fiber connector termination (i.e., not special): jacket stripper, buffer stripper, industry-standard crimp tool with two hexagonal cavities, high-quality scissors (able to cut aramid strength members), scriber, manual polishing puck, polishing film (usually two grits), polishing pad, dry wipes, safety glasses, debris container (or masking tape), marker pen, microscope (100X minimum).

Note that the cost of the special tools as noted for the crimp and no epoxy/no polish methods can vary from manufacturer-to-manufacturer. Some of the tools have an insignificant cost, some cost a few hundred dollars.

The Crimp style termination method typically does not need an industry-standard crimp tool because the installation tool includes the required crimp cavities.

The No epoxy/No polish termination method does not require the following "standard" tools: industry-standard crimp tool (all crimping is performed via the installation tool), scriber, manual polishing puck, polishing film, polishing pad, microscope.




The Ten Commandments of Fiber Safety

Handling optical fiber is not inherently dangerous as long as some basic safety precautions are followed. You can significantly reduce the risk of injury by knowing the risks associated with working with fiber and following some simple safety guidelines.

Prevent external and internal injuries

Fiber should be handled with care during preparation and termination. A bare optical fiber strand is difficult to see and can easily penetrate the skin. Keep your work area clean and use a dark, resilient work surface (such as a black foam mat) to prepare and terminate fiber. This type of work surface will make small scraps of fiber more visible and will minimize incidental movement, breakage and loss of bare fibers. Also, impact of a fiber onto a hard surface, such as a tabletop without a mat, may cause the fiber to "bounce back" and become lost or lodged into your skin, eyes or clothing.

Keep a disposal container nearby and discard scraps promptly. In the event a fiber splinter becomes lodged in the skin, it should be removed immediately using tweezers. Avoid touching or rubbing your face and eyes to minimize possible transfer of glass particles. Because ingested fibers can cause internal damage, it is also important not to eat or drink during the termination process or in areas used to prepare or terminate optical fiber cables.

Protect your vision

Broken bits of fiber are not the only danger associated with working with optical fiber. Overexposure to a live fiber may cause damage to the retina. Two general types of light sources are used to transmit information over fiber. Light-emitting diodes (LED's) are commonly used for multimode fiber applications, whereas different types of lasers can be used for either singlemode or multimode transmission. Although LED's have a relatively low power and are less likely to cause eye damage, it is strongly recommended that the same precautions be observed, regardless of the type of fiber or light source being used. Both types of sources use wavelengths that cannot be detected by the human eye. Therefore, it is impossible to visually determine if a damaging light source is present until it is too late. Take no chances. Do not look directly into any live fiber, regardless of the type of fiber or light source being used.

Handle consumables with care

Some of the bonding and cleaning materials used to prepare fiber are flammable. Caution should be used when working with and disposing of these materials. Never smoke while working with these materials. Always work in a ventilated area and observe handling precautions provided with material safety data sheets that accompany solvents and adhesives used for fiber termination.

Use the 10 tips below to ensure maximum safety while working with optical fiber:

Prevent external and internal injuries

  1. Use a dark, resilient working surface to provide contrast for the fibers and to reduce the potential for fiber "bounce back".

  2. Dispose of all cleaved pieces of fiber into a debris container or onto a piece of masking or electrical tape. Never dispose of loose glass fibers into a wastebasket and never allow loose pieces of glass to accumulate.

  3. Use tweezers to remove any piece of fiber immediately after it penetrates the skin. Delays in removal increase the risk of infection and difficulty of extraction

  4. Do not eat or drink in the termination area. Ingested fibers can cause internal damage.

  5. Protect your vision

  6. Never look into the end of a terminated connector to determine if the fiber is live.

  7. Use a power meter to test installed fiber cabling, both to determine the presence of light as well as to assess continuity and the optical integrity of cabling links and channels. Even when performing visual continuity checks on cable assemblies, it is strongly recommended that the source be detected by holding the fiber up to a contrasting surface rather than looking directly into the fiber.

  8. Wear safety glasses with side shields to protect the eyes from errant pieces of fiber. However, safety glasses will not protect the retina from light damage.

  9. Do not touch your eyes or face at any time while handling bare fiber. Wash your hands immediately after working with bare fiber or solvents.

  10. Use caution when handling solvents, adhesives and other consumables

  11. Observe recommended precautions when working with adhesives and solvents. For example, do not smoke and always work in areas with sufficient ventilation to minimize the risk of fire and other material hazards. Even when no flammable solvents are present, smoking increases the likelihood of hand-to-mouth transfer of glass particles.

  12. Use an alcohol-soaked wipe only once and then dispose of it properly. One time use of cleaning materials eliminates the possibility of injury from glass fibers that may have been deposited on the wipe. This practice also reduces the potential of depositing debris onto the fiber or connector ferrule.



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