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Fiber-Optic Cleavers and Scribes

  • Ruby Scribe for Cleaving Excess Fiber
  • Ceramic Scribe for Cleaving Polyimide- or TECS-Coated Large-Core Fiber
  • Suspension Fiber Cleaver for Consistent 0.5° Cleaves
  • Disposal Unit for Cleaved Fiber


Fiber Cleaver


Ruby Fiber Scribe

Close-Up View


Disposal Unit


Ceramic Fiber Scribe
(Pack of 5)

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Thorlabs offers the S90R ruby-tipped scribe, the CSW12-5 ceramic scribe, and the XL411 suspension cleaver as solutions for easy, manual cleaving of fibers. The S90R ruby-tipped wedge scribe can be used for easy scribing of excess fiber from ferrules in the connectorization process. The CSW12-5 ceramic scribes are optimal for scoring and cleaving hard-coated and large-core fiber. The XL411 suspension cleaver is an ideal solution for the high-quality, repeatable cleaves needed for fusion splicing of fiber optics. The FTDU provides a simple safe solution for disposing of all cleaved fiber ends. We recommend using such a disposal unit to protect against injuries caused by fiber shards. In addition, Thorlabs offers a variety of complementary products and tools for fiber termination.

Scoring a fiber with a ruby scribe
Click to Enlarge
Figure 2: Hold the ceramic scribe at a 45° angle to the fiber.
Scoring a fiber with a ruby scribe
Click to Enlarge
Figure 1: Hold the ruby scribe perpendicular to the fiber.

The S90R and CSW12-5 scribes are convenient, easy-to-use tools for scoring or cleaving fiber. They are used extensively when connectorizing or polishing fibers. Below is a simple step-by-step description on the most common usages for these scribes. For more detailed information on connectorization or polishing of fibers, please refer to the FN96A connectorization guide.

Fiber Scoring

Scoring is a technique for cleaving a fiber that utilizes a scribe to make a small cut in the fiber (i.e., a score) that becomes a stress point for cleaving. Below are descriptions on how to use the S90R ruby scribe and the CSW12-5 ceramic scribe.

For the S90R, the cutting edge of the ruby scribe must be held perpendicularly to the protruding fiber. Figure 1 shows a fiber, protruding from a connector, undergoing scoring by a ruby scribe. The
CSW12-5 ceramic scribe should be held at a 45° angle to the fiber so that the straight edge (i.e., any edge on the un-engraved side) is in contact with the fiber. As shown in Figure 2, this will result in the engraved side facing upwards. The engraved metric scale on the CSW12-5 can used to ensure repeatable cuts.

While restraining the fiber, gently drag the scribe across the fiber at the desired location. Different optical fiber types will require different amounts of scoring. It will not take a lot of force to score the fiber, and the fiber should not break during scoring. If the fiber does break during scoring, it may produce a jagged edge that cannot be polished correctly; hence, care must be taken to prevent breakage during scoring. Over time, as the cutting edge progressively deteriorates, more pressure will be needed to score the fiber; keep in mind that undue pressure can lead to poor cuts. Once a fiber has been scored, it can be easily cleaved. From the scored side of the fiber, gently squeeze the fiber tip and pull straight away from the rest of the fiber (see Figure 4). Avoid bending or flexing the fiber. This should be all the force necessary to create a clean cleave. Multimode fibers may require slightly more force due to their larger
core diameter.

Preparing for cleaving
Click to Enlarge
Figure 3: Ensure the fiber is secured and taut when cleaving or scoring.
Cleaving a Fiber
Click to Enlarge
Figure 4: Pull the fiber straight back until the fiber is cleaved to ensure a clean break. Do not twist or bend the fiber.

Fiber Cleaving

Cleaving a fiber is a technique that is very similar to scoring. After preparing a fiber for cleaving, clean the bare fiber using a lint-free wipe moistened with isopropyl alcohol. Once clean, tape one end of the fiber to a bench or work station; leave about 6 mm between the edge of the table and tape. Figure 3 shows a fiber cable prepped for cleaving. When using this technique, it helps to secure the free end of the fiber to a support in order to help prevent against breaking the fiber on the edge of the table. Even the weight from a short section of fiber can be enough to cause the fiber to break.

To start the cleave, pull the fiber taut and keep tension in the fiber as you cleave. Bring the scribe toward the fiber at a 45° angle for the ceramic scribe (see figure 2) or at a perpendicular angle for the ruby scribe (see figure 3). It's important to keep the proper amount of pressure on the scribe during this process. If too much pressure is applied to the scribe, the fiber will break, resulting in a jagged end, which may not be able to be polished correctly. Too little pressure and the fiber will not score enough to cleave cleanly. After the fiber has been scored, place a drop of water on the cleave site. Then apply pressure to the taped end of the fiber and, like with the scoring above, pull the fiber straight back until you cleave the fiber (see figure 4). Try to avoid any bending or flexing of the fiber, as this could affect the cleave.

The end of the fiber may be inspected with an eye loupe or microscope. A good cleave will be flat across the fiber and perpendicular to the optic axis. There should be no 'tag' (i.e., protrusion) from the edge of the fiber. The region where the initial scribe was made may be visible. It should be less than 5% of the core diameter. If the cleave is not acceptable, repeat the cleaving process.

XL411 SmartPack Packaging
Click to Enlarge

XL411 Packaging

Smart Pack

Item # % Weight
XL411 25.19% 1.47 kg

Smart Pack

  • Reduce Weight of Packaging Materials
  • Increase Usage of Recyclable Packing Materials
  • Improve Packing Integrity
  • Decrease Shipping Costs

Thorlabs' Smart Pack Initiative is aimed at waste minimization while still maintaining adequate protection for our products. By eliminating any unnecessary packaging, implementing packaging design changes, and utilizing eco-friendly packaging materials for our customers when possible, this initiative seeks to improve the environmental impact of our product packaging. Products listed above are now shipped in re-engineered packaging that minimizes the weight and the use of non-recyclable materials.b As we move through our product line, we will indicate re-engineered packages with our Smart Pack logo.

  • Travel-based emissions reduction calculations are estimated based on the total weight reduction of packaging materials used for all of 2013’s product sales, traveling 1,000 miles on an airplane, to provide general understanding of the impact of packaging material reduction. Calculations were made using the EPA’s shipping emissions values for different modes of transport.
  • Some Smart Pack products may show a negative weight reduction percentage as the substitution of greener packaging materials, such as the Greenwrap, at times slightly increases the weight of the product packaging.

Posted Comments:
cbargsten  (posted 2018-12-18 10:26:42.923)
Please offer the blade for the S90R as a separate replacement item so we don't have to purchase a new handle every time. Thank you!
mmcclure  (posted 2018-12-18 01:47:54.0)
Hello, thank you for contacting us. Although we currently cannot offer replacement blades for the S90R as a standalone product, I have communicated your suggestion to our development teams.
user  (posted 2018-11-20 13:38:32.423)
Can XL411 fiber cleaver be used for cleaving hard-coated fibers? Thanks.
YLohia  (posted 2018-11-27 05:04:02.0)
Thank you for contacting Thorlabs. In general, it is a good idea to strip the coating before cleaving. Please reach out to us directly at with your inquiry so we can discuss your specific requirements/coating.
ischoi1205  (posted 2017-02-23 09:58:50.227)
Hello, this is In Seok Choi from EOtechnics. We’d like to purchase the Ruby DualScribe Fiber Optics Scribe(1 ea). Please send us the quotation. Thank you Sincerely In Seok Choi ----------------------------------------------- In Seok Choi R&D Center/Senior Engineer EOTECHNICS Co., Ltd. 91 Dongpyeonro Anyang Korea 431-815 Mobile: +82-10-3446-2074
jlow  (posted 2017-02-24 09:19:11.0)
Response from Jeremy at Thorlabs: To request a quote, you can contact us at or choose "Request a Quote" during the checkout process.
aralisantosh  (posted 2014-09-05 03:19:23.927)
Can we replace the blades? If yes, what is the product number for the purchase of the the blade? Reply asap. Regards, Santosh
besembeson  (posted 2014-09-10 03:22:38.0)
Response from Bweh: Unfortunately at this time, we don't provide replacement blades for the S90R which has an almost equivalent price with the S90R.
kareem_ashraf36  (posted 2008-03-24 08:16:07.0)
Great tool and i also like to know about more latest tools.

Ceramic Fiber Scribes

Close-Up of BladeClick for Details
The CSW12-5 has Straight and Micro-Serrated Edges
Close-Up of BladeClick to Enlarge
Cleaving Fiber Optic Cannula with the CSW12-5
  • Durable 1" x 2" x 0.03" Aluminum Oxide (Al2O3) for Longterm Use
  • Capable of Scoring Optical Fiber with Polyimide, TECS, or Polymer Coatings
  • Engraved Metric Scale for Measuring Short Fiber Lengths Quickly
  • Convenient for Quickly Cleaving Optogenetics Cannula to Desired Length
  • Sold in Packs of 5

These Ceramic Fiber Optic Scribes have four straight edges for scoring fiber optics and four micro-serrated edges for glass-lined metal capillary and stainless steel hypodermic needle stock. Its hard ceramic (98% Al2O3) edges are capable of cleaving polyimide-, TECS-, or polymer-coated optical fiber. These scribes feature a large surface area for secure handling, are suitable for small or large core fibers, and have an engraved metric scale that can be used for quick and repeatable measurements. These ceramic scribes are autoclavable for applications that require sterile procedures.

The straight edge is any edge on the un-engraved side, and the serrated edge is any edge on the engraved side. The edges can also be distinguished by running your fingernail along each edge; the straight edge will feel smooth, whereas the serrated edge will be noticeably rough. See the diagram to the right for details. The CSW12-5 scribes are designed for longterm use but will eventually dull. When all four sides of the scribe become dull, discard and replace with a fresh scribe. This will help to minimize adding undue force onto the fiber due to a dull edge.

For information on scoring fiber with the ceramic fiber scribe, please see our Cleaving Guide tab above.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
CSW12-5 Support Documentation
CSW12-5Ceramic Fiber Optic Scribes, 5 Pack

Ruby Fiber Scribe

Close-Up of Blade
Click to Enlarge
Ruby Fiber Scribe has a Reversible Blade with 30° Bevel
  • 30°, Single Bevel, Ruby Tip
  • 5.2 mm to 5.5 mm Long Contact Area Aids Cleaving of Large-Core Fiber
  • Cleave Bare Fiber to Produce Optical Quality Surfaces
  • Scribe Excess Fiber from the Connector Ferrule in Preparation for Polishing

This Ruby Fiber Scribe has a 30°, single bevel, ruby blade with a 5.2 mm to 5.5 mm long contact area. The blade is reversible, which doubles the life of the scribe (see below for details). However, replacement blades are not available. The soft, non-slip grip provides precise control during scribing. The scribe is approximately 5" long from end to end. Each scribe comes with a clear safety cap to protect the blade from damage when not in use.

Blade Reversal
To reverse the blade, unscrew the knurled end of the scribe and pull it slightly out of the handle. This releases the blade mount. Push the knurled end back into the handle. The blade and its mount will be pushed away from the handle allowing the blade to be removed, flipped, and reinserted. While holding the blade and mount in the handle, screw the knurled end back in, securing the blade.

For information on scoring and cleaving fiber with the Ruby Fiber Scribe, please see our Scribe Guide Tab above.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
S90R Support Documentation
S90RRuby DualScribe™ Fiber Optic Scribe

* Orders for in-stock bare fiber placed by 3:00 PM ET are eligible for same-day shipment.

Fiber Cleaver

  • Precision Engineered to Produce Consistent 0.5° Cleaves
  • 3-Step Cleaving Process Clearly Indicated on Unit
  • Switchable Blade Position
  • Mechanical Design Allows for Easy, Precise Blade Replacement
  • For Use with Standard Ø125 µm Cladding and Buffers Ranging from Ø250 to Ø900 µm
  • Ribbon Fiber Option (Requires Adapter Plate Sold by Alcoa Fujikura)

The XL411 Suspension Cleaver has an easy to follow 3-step process that produces consistent 0.5° cleaves. For ease of use, this sequence is clearly indicated on the tool making this an ideal instrument for laboratory or production environments. Unlike rotating cleavers where the blade accesses the fiber from the side, the flat blade of the XL411 cleaves the fiber from the top, which results in the best cleave possible.

The blades on this suspension cleaver last longer than traditional cleavers because the point of contact between the flat, rectangular blade and the fiber can be moved to reduce blade wear, providing up to 5000 cleaves per blade. In addition, the precision mechanical design of the XL411 allows the blade to be replaced quickly and precisely in any location.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
XL411 Support Documentation
XL411High Precision Fiber Cleaver, Switchable Blade Position
XL410B Support Documentation
XL410BHigh Precision Fiber Cleaver Replacement Blade

Fiber Optic Disposal Unit

  • Safe Solution for Disposing of Cleaved Fiber Ends
  • One Circular and One Rectangular Covered Hole in Lid
  • Dimensions (L x W x H): 2.75" x 2.75" x 6" (6.99 cm x 6.99 cm x 15.24 cm)
  • Disposable: Do Not Reuse

The FTDU offers a safe solution for disposal of cleaved fiber ends, epoxy and syringes, and other sharp objects. This high-density polyethylene (HDPE) bottle features a translucent lid with one circular and one rectangular hole in it (see the photo to the right). Both of these holes have individual covers that snap closed to keep the contents inside the unit. Tabs on the side of the lid hold the covers open for hands-free use. The two hole covers are connected by a plastic tab. Cut, or pull, the covers apart to use the holes separately.

To use, insert sharps into one of the holes in the lid. Do not remove the lid itself from the unit. Use the "Contents" space on the label to clearly indicate what is inside. To protect against spills, keep the holes covered when not inserting sharps. When it is full, securely cover both holes in the lid by inserting the tab on the cover into the slot in the lid and dispose of the canister according to the contents. Do not fill the sharps container past the indicated "Full" line on the label. Do not reuse this unit; it is a one-time-use container only.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
FTDU Support Documentation
FTDUFiber Optic Disposal Unit
5-8 Days
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