Thorlabs offers both the S90R wedge 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 XL411 suspension cleaver is an ideal solution for the high-quality, repeatable cleaves needed for fusion splicing of fiber optics. In addition, Thorlabs offers a variety of complementary products and tools for fiber termination. For further details, please Click Here.

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The S90R ruby scribe is a very convenient, easy-to-use tool for scoring or cleaving fiber. It is used extensively when connectorizing or polishing fibers. Below is a simple step-by-step description on the most common usages for this ruby scribe. For more detailed information on connectorization or polishing of fibers, please refer to this pdf.

Fiber Scoring

Scoring is a technique for cleaving a fiber that utilizes the ruby scribe to make a small cut in the fiber (i.e., a score) that becomes a stress point for cleaving. The picture to the right shows a fiber, protruding from a connector, undergoing scoring by a ruby scribe.

To score a fiber, the cutting edge of the scribe must be held perpendicularly to the protruding fiber. Then very lightly score the fiber in the desired location. It will not take a lot of force to score the fiber, and the fiber should not break during scoring. The scribe will need only to gently touch the fiber in order to properly score it for a clean cleave. 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.

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. 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.

Fiber Cleaving

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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. The image to the left 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 taunt and keep tension in the fiber as you cleave. Bring the scribe towards the fiber, keeping it perpendicular, as shown in the image to the bottom left. 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 unable 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 the image to the bottom right). 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.

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