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ASK FOC

Have a technical question for Fiber Optic Center?

Please email your question to AskFOC@focenter.com and we will respond ASAP. 

In addition to replying, we will post your question and our answer here on the AskFOC page.  Everyone remains anonymous when we post so feel comfortable asking your questions.  You can also search to see if your question has already been answered in the FAQs section below.

Information on SMA connector over polishing

QUESTION: Where can I get some information on SMA connector over polishing?   ANSWER: For other types of actively used connectors, SMA for example, the design intent of this connector has a specific pre-polish length and final after polish length of .3860”-.3863”...

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Which epoxies cause allergic reactions and which do not

QUESTION:  Which epoxies cause allergic reactions and which do not?     ANSWER: Almost all epoxies used in the fiber optic industry are two-part epoxy systems consisting of a resin and a hardener or activator.  All the chemicals in these two-part epoxies can...

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How can I identify crystallization in epoxies?

QUESTION: How can I identify crystallization in epoxies?   ANSWER: If you put a glass of water in the freezer for a few minutes, you’ll see ice crystals begin to form as the water changes to ice (its solid state). Similarly, crystals often form in epoxies....

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What happens if you undermix epoxy?

QUESTION: What happens if you undermix epoxy?     ANSWER: In fiber optic cable assembly applications, most epoxy package sizes are quite small – just a few grams – so undermixing is typically not an issue. While mixing the resin and hardener (Part A and Part...

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The importance of measuring Insertion Loss and Return Loss

QUESTION: Why is it important to measure Insertion Loss and Return Loss?   ANSWER: It’s quite simple: Your customers demand it. Your customers need to know that you’ve tested every fiber optic jumper and cable and have acquired accurate IL/RL measurements that...

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The “weakest link” of a connectorized cable assembly

QUESTION: What is the “weakest link” of a connectorized cable assembly?   ANSWER: In terms of long-term reliability, the “weakest link” of a connectorized cable assembly is the area within the ferrule which contains the strip “transition point” (where the...

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Epoxy curing tips for when issues occur

QUESTION: Does FOC has some epoxy curing tips for when issues occur?   ANSWER: Tips regarding epoxy curing issues: To validate your epoxy curing process, we recommend following the Telcordia GR-326 adhesive testing standard (section 4.4.4.2). Avoid placing curing...

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Differences between Viavi Sidewinder and Sumix Manta

QUESTION: FOC promotes/sells the Viavi Sidewinder but I have heard that some people are using and happy with the Sumix Manta.  Do you also sell that or know the differences between them?   ANSWER: FOC has selected the Viavi Sidewinder with our first-hand...

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Typical steps for terminating a fiber

QUESTION: What are the typical steps for terminating a fiber?   ANSWER: A typical fiber is “terminated” through the following steps: Fiber is stripped and cleaned. Epoxy is prepared and injected into a ferrule assembly (ferrule pressed into a ferrule-holder)...

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The ideal fiber height for a fiber optic connector

QUESTION: What is the ideal fiber height for a fiber optic connector?   ANSWER: This is a common (and perplexing) question for many and driven by our industry’s various specifications for fiber height. The specification dictated by IEC’s international standards...

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The connector with the longest history

QUESTION: Which connector has the longest history?   ANSWER: The first connector to be accepted as a widely used standard in the early days of the fiber optic industry, in the late 1970s, was designed by Amphenol in CT as a variation of their coaxial electrical...

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Are polymer plastics isotropic?

QUESTION: Are polymer plastics isotropic?   ANSWER: Most polymer plastics are inherently isotropic (that is, that is they have no directionality in their optical properties).   However, when formed in the injection molding process the polymer is melted,...

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Is Laser cleaving suitable for every assembly operation?

QUESTION: Is Laser cleaving suitable for every assembly operation?   ANSWER: The investment for cleaving systems is still significant and a semi-automated process might look attractive but the financial numbers need to reflect the improvements. An initial...

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Primary indicator of over polished connectors

QUESTION: What is the primary indicator of over polished connectors?     ANSWER: Primarily, the indicator of over polished connectors is poor repeat ability in measurements of the return loss and insertion loss. For the majority of “spring loaded ferrule...

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A little bit of Teflon

QUESTION: Where can I get a little bit of Teflon?     ANSWER: AngstromLink AL-2233 is basically that.  A Teflon-like polymer dissolved in an evaporative solvent.  To get a thin layer of ‘almost -Teflon’, make a thin layer of AL-2233 and let the solvent...

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Contamination of fixture affecting precision

QUESTION:   How can contamination of a fixture negatively affect precision and is this directly related to the milled ferrule holes?   ANSWER: All fixtures come from the factory with very precisely milled ferrule “bores”, tailored specifically to the particular...

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A way to avoid wasted epoxy

QUESTION:   Is there a way to avoid wasted epoxy?     ANSWER: Given that 2.5 grams is the smallest size that is practicably achievable, FOC recommends saving any extra epoxy in a secondary dispensing container (like a syringe), frozen -40°C.  -40°C...

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Example of micro imprinting

QUESTION: What is an example of micro imprinting?     ANSWER: One of the best examples of wafer level optics is the camera module on your mobile phone. The basic idea is to fabricate layers of microlenses that are stacked up to make the complete optical...

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Choice of epoxies critically important

QUESTION: Are the choice of epoxies critically important and if so, why?     ANSWER: The choice of epoxies is critically important. Most Telco/Data and OSP connectors are assembled with two part epoxies that provide high tensile strength, excellent bonding...

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For fibersect, the resulting cut roughly equivalent to

QUESTION:   For fibersect, what is the resulting cut roughly equivalent to?   ANSWER: When cleaving ferrule in preparation for polishing, it is irrelevant if the cleaved end-faces are smooth or rough texture from the resulting cut BUT, to answer the question, for...

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Homemade pre-mixed and frozen epoxy real?

QUESTION:   Is homemade pre-mixed and frozen epoxy real?   ANSWER: Homemade pre-mixed and frozen epoxy is the equivalent to making your own pre-mixed and frozen epoxy, which may take some trial and error, but can ultimately save time and solve the epoxy waste...

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Methods of cross sectioning fiber optic connectors

QUESTION:   How many methods of cross sectioning fiber optic connectors exist?   ANSWER: There are currently three methods of looking inside a fiber optic connector: Non- Destructive X Ray Non- Destructive Sonar Destructive Cross Sectioning These methods help...

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Actual cut distance that the fibersect can achieve

QUESTION:   What is the actual cut distance that the fibersect can achieve?     ANSWER: The actual cut distance that the fibersect can achieve is as close as 30-40um from the face of the ferrule.     ADDITIONAL CONTENT & RESOURCES: Category...

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How tight is the buffer on the cable that I am providing?

QUESTION: How tight is the buffer on the cable that I am providing?   ANSWER: I have been asked about this so many times, I wrote a blog article on this exact question. Is it a “true tight buffer” or is it “semi tight” or “loose tight buffer” or one of the other...

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When Bi-Directional makes sense

QUESTION: When does Bi-Directional make sense?    ANSWER: Bi-Directional make sense if you can use the launch and receive test method and your jumps have the same connectors on each end.  Some good product types for this are MTP to MTP jumps and large...

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Why Scratches Appear After Using the Final Film

QUESTION: Why Do Scratches Appear After Using the Final Film?   ANSWER: Ironically, we are asked this question so frequently, we wrote a blog on this exact subject. When scratches appear after using the final film, this typically relates back to earlier...

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Automation and fiber optic assembly houses

QUESTION:   Why is automation so difficult for fiber optic assembly houses?    ANSWER: Automation is difficult because there’s a lack of standardization, and we’re not even speaking about standardization in one particular connector style.  Even the...

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Specialty optical preforms strength and deposition issues

QUESTION: We manufacture specialty optical preforms and fibers and are looking for solutions to our strength and deposition issues.  Can you help with that challenge?   ANSWER: Fiber Optic Center does offer preform fabrication consulting services to manufacturers...

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Considerations for cleaning fluids being transported

QUESTION: What are the considerations for cleaning fluids being transported?   ANSWER: Considerations for cleaning fluids being transported: Air Shipment Requirements HAZMAT Restrictions Spill and Leak Concerns     ADDITIONAL CONTENT & RESOURCES:...

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General best practices for cleaning connectors

QUESTION: Are there general best practices for cleaning connectors?   ANSWER: General Best Practices: Never look directly into a connector with the bare eye Inspect, clean if necessary & re-inspect Reusing wipes & sticks causes cross contamination  ...

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Deposition tube diameters vary from run to run

QUESTION: Our deposition tube diameter varies from run to run.  Do you have information on how to control that?   ANSWER: When you deposit barrier and core layers, your goal is consistent thickness every time. However, as you’re well aware, the burner flame...

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Quartz tube-cleaning process best practices

QUESTION: Do you have any information on quartz tube-cleaning process best practices?   ANSWER: The tube-cleaning process is a critical part of your preparation. Companies like SG Controls offer tube-cleaning machines with programmable cycles. The first...

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Best practices for wiping connectors

QUESTION: Are there best practices for wiping connectors?   ANSWER: Best Practices for Wiping Connectors: Wipe connectors in a single direction Always wipe MT based connectors (i.e MPO) in a single direction vertical direction   Tilt end face for APC so...

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Can you use expired epoxy?

QUESTION:   Can you use expired epoxy?   ANSWER: Epoxy does have a shelf life and the physical properties will change over time. Epoxy manufacturers recommend you do not use epoxy that has reached its expiration date. If unusual circumstances require you to use...

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Best practices for sticks & swabs

QUESTION: Are there best practices for sticks & swabs?   ANSWER: Best Practices for Sticks & Swabs: Rotate stick at least 6X  in a single direction Limit force to about the same pressure you would use for a writing pen Never excessively scrub the end face...

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Best practices for cleaning fluid?

QUESTION: Are there best practices for cleaning fluid?     ANSWER: Best Practices for Cleaning Fluid: Use hermetically sealed containers to avoid cross contamination Less is more – Dispense just enough to clean a connector     ADDITIONAL CONTENT...

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Where does dust based end face contamination come from?

QUESTION: Where does dust based end face contamination come from?   ANSWER: There are two basic sources of dust based contamination. Wear Debris The most common source is wear debris caused by the contact friction of inserting a connector into the adapter. ...

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Can I modify the software for Viavi OCETS?

QUESTION:   Can I modify the software for Viavi OCETS?   ANSWER: No, OCETS results will be accepted by certifying authorities, the software is locked down to avoid “errors”.     ADDITIONAL CONTENT & RESOURCES: Category Resource: FOC Test Page   Find...

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Regarding OCETS, does Viavi supply the chamber?

QUESTION: Regarding OCETS, does Viavi supply the chamber? ANSWER: No, Viavi does not supply the chamber for OCETS.  Chambers have complex power and water supply requirements and it is preferred to deal directly with the manufacturer.     ADDITIONAL CONTENT...

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How do I know I need OCETS?

QUESTION:  How do I know I need OCETS?   ANSWER: If you need formal Telcordia of Verizon certification, Optical measurements during several temperature and humidity challenges will be required, OCETS is the accepted industry standard tool for this.  ...

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IL effect of Return Loss Clarification

QUESTION: In looking up the IL effect of Return Loss, I found definitions in your FOC Glossary (https://focenter.com/foc-glossary/) for IL, IL/RL, RL.  In addition to these definitions: Insertion Loss: The ratio between the power received at a specified load before...

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What is OCETS Plus?

QUESTION: What is OCETS Plus?   ANSWER: OCETS Plus is an Environmental Test System.  An integrated automated test facilities for testing long-term reliability of optical components while subjected to environmental stress conditions in a temperature/humidity...

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