fiber strippers (original) (raw)

Definition: precision tools that remove a defined length of coating from a fiber

Alternative terms: coating strippers, fiber coating removal tools, jacket/buffer strippers

Category: fiber optics and waveguides

• optics
  • fiber optics
    * fibers
    * fiber connectors
    * fiber-optic adapters
    * fiber couplers
    * fiber-optic pump combiners
    * fiber bundles
    * fiber endface inspection
    * cleaving of fibers
    * fiber cleavers
    * fiber joints
    * fiber splices
    * fiber Bragg gratings
    * fiber cables
    * fiber coatings
    * fiber strippers
    * mechanical fiber strippers
    * thermal strippers
    * non-contact strippers
    * fiber recoaters
    * fiber coils
    * fiber collimators
    * fiber launch systems
    * fiber lenses
    * fiber loop mirrors
    * fiber patch panels
    * fiber shuffles
    * fiber-optic attenuators
    * fiber-optic plates
    * fiber-optic tapers
    * (more topics)

Related: fibersfiber fabricationfiber connectorsfusion splicing of fibers

DOI: 10.61835/jtk Cite the article: BibTex BibLaTex plain textHTML Link to this page! LinkedIn

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Contents

What are Fiber Strippers?

Optical fibers are typically protected with fiber coatings made from polymers such as acrylate, silicone or polyimide. For splicing, connectorization or other processing, these coatings must be removed. Fiber strippers are precision tools that reliably and cleanly remove a defined length of coating (often 30–40 mm) from a fiber end so that the bare glass is exposed without scratching or nicking it. In some applications, “window strip” operations are required, where a short section of coating is removed from the middle of the fiber rather than from the end — for example, for creating fiber Bragg gratings.

Stripper tools are available in various forms (see below). They may be tailored to specific fiber and coating types, and use different operating principles (mechanical, thermal, or non-contact methods).

Most strippers are designed for standard telecommunication fibers with a 125 µm glass cladding diameter (with tight tolerances) and a typical coated diameter around 250 µm. However, thinner specialty fibers — for example with 200 µm coatings — are increasingly used to reduce cable diameter and increase fiber counts; this affects the required hole sizes on handheld strippers and the settings on automated systems. There are also strippers for plastic optical fibers (POF).

Some fiber strippers also remove tight buffers (e.g., 900 µm) and, in some cases, the larger jackets used in fiber cables.

Fiber Strippers in the Workflow

Typical preparation steps, beginning with a roughly cut fiber end from a spool, are:

• Stripping: One strips the fiber, i.e., removes the coating over some length of e.g. 30 mm. The actually required strip length may be specified by the supplier of a fusion splicer or fiber connectors to be applied.
• In cases where a longer length needs to be stripped, one should usually not strip more than ≈50 mm at a time in order to avoid damage to the fiber.
• Cleaning: One often needs to clean the bare fiber end, i.e., to fully remove any coating residues (and any chemical solvents applied). Typically, one uses a lint-free wipe moistened with high-purity alcohol or a dedicated fiber cleaner agent. See the article on cleaning of fiber ends for details.
• Cleaving: Finally, the fiber can be cleaved to prepare a well-defined fiber end.

The prepared end can then be connectorized or fusion spliced. Before that, further inspection — such as a quick bend test or checking for small damages with a fiber microscope — may be performed. After processing, one may apply a fiber recoater, applying a new coating.

When working with fiber cables that include additional protective layers, one needs to remove those layers first to expose individual fibers.

Types of Fiber Strippers

Fiber strippers vary in the fiber diameters and coating materials they support, and they differ in convenience, throughput, reliability, and cost. Production requirements — such as adjustable strip length, automation, RFID/recipe control, and battery operation — may influence the choice.

Mechanical Handheld Strippers

These widely used field tools employ a precisely sized hole and V-groove edge to score the coating. A straight axial pull (with no twisting) then peels the polymer from the glass. Tight-tolerance jaws are designed to avoid contact with the glass; using an incorrect cavity or a worn/contaminated tool can nick the glass and create crack initiation sites.

Common variants of mechanical strippers include:

• Single-hole: These are often suitable for 250 µm acrylate fiber coatings on 125 µm glass. There are also special variants e.g. for thinner 200 µm coatings.
• Two-hole and three-hole “combo” strippers: Such devices cannot only remove standard coatings, but also tight buffers and possibly jackets.

Mechanical strippers are inexpensive and fast but require correct sizing, clean jaws, and careful application to avoid glass damage.

Thermo-mechanical Strippers

Thermal tools soften the coating with heat before pulling, reducing the stripping force. This is useful for multi-fiber ribbons and for tough coating materials.

A common method is to apply electrically heated jaws, heating the section of coating to be removed. Temperatures around 80–120 °C are sufficient for acrylate coatings, while tight buffers and silicon-based coatings require 120–150 °C, and polyimide coatings even 250–350 °C. Required temperatures for specialty non-silica or metal-coated fibers can vary widely. Heating may also be combined with chemical or plasma assistance.

Some bench thermal units strip single fibers or specialty buffers with adjustable temperature, pull speed, and strip length. There are also ribbon thermal strippers for processing whole fiber ribbons.

Thermal strippers need some electrical power. Battery-powered devices for field use can run hundreds of cycles per charge.

Some thermal strippers pair with fusion splicers.

Strippers for Specialty Coatings

• Polyimide coatings are used in harsh environments; they are harder to remove than acrylate coatings. One may then apply special mechanical, thermo-mechanical or plasma systems.
• Hard-clad silica fibers (HCS fibers) need special stripping inserts and diameters. Non-silica fibers, e.g. some fluoride fibers and chalcogenide fibers, can be rather delicate, making standard stripping tools unusable. Suppliers should be able to provide advice on suitable stripping procedures.
• Non-contact methods: Special hot air stream, laser or plasma systems can ablate coatings — sometimes including polyimide, carbon, or metal layers — with high dimensional control and no blade contact. They are favored for ultra-high-reliability and “window strip” applications.

Chemical Stripping

Chemical stripping uses strong solvents or acids to remove optical fiber coatings. It is now rare in routine telecom work, but still encountered in research labs or when handling certain coating types or specialty fibers like fragile fluoride fibers where other stripping methods do not work well. For example, polyimide, silicone, or carbon overcoats can be treated that way, and window stripping is possible over longer lengths than with mechanical tools.

The coated fiber section is immersed in or exposed to a concentrated chemical reagent that dissolves or degrades the polymer coating. Sometimes, a hot bath is used to accelerate the process. After a specified dwell time, the softened coating must be thoroughly rinsed away, leaving the bare glass, and dried before cleaving or splicing.

Typical reagents historically used include:

• Concentrated sulfuric acid (sometimes heated to 150–180 °C) has been used especially for tough coatings like polyimide.
• Methylene chloride, N-methyl-2-pyrrolidone (NMP), or phenol-based solvents are suitable for acrylate and silicone coatings.

As chemical stripping tends to be hazardous, it requires trained personnel, proper protective equipment and strict protocols. Safer mechanical or non-contact alternatives are preferred today.

General Precautions

Avoiding Fiber Damage

Note that stripping disturbs the fiber's pristine surface. Poor technique can introduce flaws that reduce tensile strength. Telecommunications fiber is proof-tested (commonly 100 kpsi ≈ 0.69 GPa) during manufacture, but local handling damage from nicked strips can cause failures later.

Therefore, correct tools, cleaning and immediate protection are essential:

• Tools (e.g. stripping claws) and the whole working area must be kept clean.
• Tools or their parts must be replaced when defects are noticed, e.g. worn claws, rising strip force, or ragged coating edges.
• The tool supplier's application notes should be carefully observed.

Quality Control

Ideally, after stripping there are no coating remnants, and the glass is not scratched or nicked, so that its full strength is preserved. For thorough testing, one may use a fiber microscope, which can reveal tiny remnants, microscopic scratches and the like.

Thorough quality control is particularly needed when there are indications that the stripping process did not work well — for example, when a high stripping force was needed, when the strip length is inconsistent, or when a window strip leaves “shoulders”.

Safety

Various safety precautions are important:

• One should wear safety glasses with side shields to protect eyes from flying shards or fiber splinters.
• Microscopic glass shards need to be managed and disposed of safely, e.g. using shard containers, tape to pick up splinters.
• Protective gloves (nitrile or cut-resistant as appropriate) prevent skin punctures from sharp glass fragments; some technicians prefer finger cots for better dexterity.
• Lab coats, long sleeves and closed shoes prevent fiber splinters from contacting skin and clothing.
• Food and drinks should be banned in the work area.
• Chemical stripping needs special precautions, such as fume hoods or local exhaust ventilation, chemical-resistant gloves and face shields.

Frequently Asked Questions

This FAQ section was generated with AI based on the article content and has been reviewed by the article’s author (RP).

What is a fiber stripper?

A fiber stripper is a precision tool used to remove the protective polymer fiber coatings from an optical fiber. This process exposes the bare glass without scratching or nicking it, which is required for tasks like splicing and connectorization.

What are the main types of fiber strippers?

The main types include mechanical handheld tools with precise blades, thermo-mechanical strippers that use heat to soften the coating, non-contact methods like hot air or laser ablation, and chemical stripping using solvents or acids.

What is the advantage of a thermo-mechanical stripper?

Thermo-mechanical strippers use heat to soften the coating before pulling it off. This reduces the required stripping force, which is beneficial for tough coatings and multi-fiber ribbons, minimizing the risk of damaging the glass fiber.

What is a 'window strip' operation?

A 'window strip' is a process where a short section of the protective coating is removed from the middle of a fiber, rather than from one of its ends.

Why is it dangerous to scratch or nick a fiber during stripping?

Scratches or nicks on the glass surface from improper stripping create flaws that act as crack initiation sites. These flaws severely reduce the fiber's tensile strength, which can lead to the fiber breaking under stress later on.

How are tough coatings like polyimide removed from fibers?

Polyimide coatings, used in harsh environments, are harder to remove than standard acrylate. They often require specialized methods like thermo-mechanical strippers at high temperatures (250–350 °C), plasma systems, or chemical stripping.

Suppliers

Sponsored content: The RP Photonics Buyer's Guide contains 16 suppliers for fiber strippers. Among them:

⚙ hardware

NYFORS offers different devices for fiber stripping:

• The AUTOPREP 2™ is a fully automated, high-speed fiber preparation unit. It strips, cleans and cleaves a fiber in less than 15 seconds. It is designed primarily for industrial applications, where accuracy, reliability and a high production yield are required. It is used for fast and chemical-free fiber preparation of acrylate-based fiber coatings and meets the highest industrial requirements of fast and consistent fiber preparation with extreme cleanliness and high fiber strength. Optimal cleaves are generated by a highly advanced and patent pending cleaving process.
• The AUTOSTRIPPER 2™ uses heated air for fast, chemical-free window stripping of optical fibers. It is suitable for acrylate coating diameters up to 550 μm. The AUTOSTRIPPER 2™ meets the need for variable and multiple window strip lengths at high strength and ultra cleanliness.
• The ULTRASONIC FC uses ultrasound at 40 kHz. It features dual cleaning positions and a large 0,7L solvent tank with programmable cleaning duration.

Bibliography

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