Cleave (fiber)
Encyclopedia
A cleave in an optical fiber
is a deliberate, controlled break, intended to create a perfectly flat endface, perpendicular to the longitudinal axis of the fiber. Since there are no crystalline planes in glass
, this process is not cleavage
in the crystallographic
sense of the word, although the techniques used and the finished result are quite similar.
A cleave is made by first introducing a microscopic fracture ("nick") into the fiber with a special tool, called a cleaving tool, which has a sharp blade of some hard material, such as diamond
, sapphire
, or tungsten carbide
. If proper tension
is applied to the fiber as the nick is made, or immediately afterward (this may be done by the cleaving tool in some designs, or manually in other designs), the fracture will propagate in a controlled fashion, creating the desired endface.
A good cleave is required for a successful splice of an optical fiber, whether by fusion
or mechanical
means. Also, some types of fiber-optic connectors do not employ abrasives and polishers. Instead, they use some type of cleaving technique to trim the fiber to its proper length, and produce a smooth, flat perpendicular endface.
High-precision optical fiber
cleavers are commercially available through a small number of specialized manufacturers, such as Nyfors Teknologi AB
, which usually also supplies other fusion splicing
accessories such as fiber optic recoaters
and stripping and preparation
equipment.
Optical fiber
An optical fiber is a flexible, transparent fiber made of a pure glass not much wider than a human hair. It functions as a waveguide, or "light pipe", to transmit light between the two ends of the fiber. The field of applied science and engineering concerned with the design and application of...
is a deliberate, controlled break, intended to create a perfectly flat endface, perpendicular to the longitudinal axis of the fiber. Since there are no crystalline planes in glass
Glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
, this process is not cleavage
Cleavage (crystal)
Cleavage, in mineralogy, is the tendency of crystalline materials to split along definite crystallographic structural planes. These planes of relative weakness are a result of the regular locations of atoms and ions in the crystal, which create smooth repeating surfaces that are visible both in the...
in the crystallographic
Crystallography
Crystallography is the experimental science of the arrangement of atoms in solids. The word "crystallography" derives from the Greek words crystallon = cold drop / frozen drop, with its meaning extending to all solids with some degree of transparency, and grapho = write.Before the development of...
sense of the word, although the techniques used and the finished result are quite similar.
A cleave is made by first introducing a microscopic fracture ("nick") into the fiber with a special tool, called a cleaving tool, which has a sharp blade of some hard material, such as diamond
Diamond
In mineralogy, diamond is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions...
, sapphire
Sapphire
Sapphire is a gemstone variety of the mineral corundum, an aluminium oxide , when it is a color other than red or dark pink; in which case the gem would instead be called a ruby, considered to be a different gemstone. Trace amounts of other elements such as iron, titanium, or chromium can give...
, or tungsten carbide
Tungsten carbide
Tungsten carbide is an inorganic chemical compound containing equal parts of tungsten and carbon atoms. Colloquially, tungsten carbide is often simply called carbide. In its most basic form, it is a fine gray powder, but it can be pressed and formed into shapes for use in industrial machinery,...
. If proper tension
Tension (mechanics)
In physics, tension is the magnitude of the pulling force exerted by a string, cable, chain, or similar object on another object. It is the opposite of compression. As tension is the magnitude of a force, it is measured in newtons and is always measured parallel to the string on which it applies...
is applied to the fiber as the nick is made, or immediately afterward (this may be done by the cleaving tool in some designs, or manually in other designs), the fracture will propagate in a controlled fashion, creating the desired endface.
A good cleave is required for a successful splice of an optical fiber, whether by fusion
Fusion splicing
Fusion splicing is the act of joining two optical fibers end-to-end using heat. The goal is to fuse the two fibers together in such a way that light passing through the fibers is not scattered or reflected back by the splice, and so that the splice and the region surrounding it are almost as...
or mechanical
Mechanical splice
A mechanical splice is a junction of two or more optical fibers that are aligned and held in place by a self-contained assembly...
means. Also, some types of fiber-optic connectors do not employ abrasives and polishers. Instead, they use some type of cleaving technique to trim the fiber to its proper length, and produce a smooth, flat perpendicular endface.
High-precision optical fiber
Optical fiber
An optical fiber is a flexible, transparent fiber made of a pure glass not much wider than a human hair. It functions as a waveguide, or "light pipe", to transmit light between the two ends of the fiber. The field of applied science and engineering concerned with the design and application of...
cleavers are commercially available through a small number of specialized manufacturers, such as Nyfors Teknologi AB
Nyfors
Nyfors Teknologi AB is a high-end supplier of advanced optical fiber handling equipment, based in Stockholm, Sweden. The company develops and manufactures equipment used in optical fiber fusion splicing, including products for stripping and preparation, testing and analysing and fiber end-face...
, which usually also supplies other fusion splicing
Fusion splicing
Fusion splicing is the act of joining two optical fibers end-to-end using heat. The goal is to fuse the two fibers together in such a way that light passing through the fibers is not scattered or reflected back by the splice, and so that the splice and the region surrounding it are almost as...
accessories such as fiber optic recoaters
Recoating
Recoating is the process of restoring the primary coating to stripped optical fiber sections after fusion splicing. In the recoating process, the spliced fiber is restored to its original shape and strength, using a recoater. The stripped fiber section is recoated by filling a recoating resin,...
and stripping and preparation
Stripping (fiber)
Stripping is the act of removing the protective polymer coating around optical fiber in preparation for fusion splicing. The splicing process begins by preparing both fiber ends for fusion, which requires that all protective coating is removed or stripped from the ends of each fiber...
equipment.
Tools
- Pen-shaped scribe (aka diamond-tip scribe or diamond wedge scribe) look like a ballpoint pen, but have a small wedge tip made diamond or other hard material. This tool is used with the "scratch and pull" technique. First the fiber is scribed perpendicular to its length. The fiber is then pulled, which breaks at the scribe. This tool requires an experienced operator to produce good cleaves.
- Mechanical cleavers clamp the fiber in the correct position before a diamond wheel or blade scribes the fiber. Then, a force is applied and the fiber gives a nice break at the scribe. Mechanical cleavers give nicer and more repeatable cleaves.
- Multifiber cleavers are used for ribbon fiber cables.
See also
- Fusion splicingFusion splicingFusion splicing is the act of joining two optical fibers end-to-end using heat. The goal is to fuse the two fibers together in such a way that light passing through the fibers is not scattered or reflected back by the splice, and so that the splice and the region surrounding it are almost as...
- Stripping (fiber)Stripping (fiber)Stripping is the act of removing the protective polymer coating around optical fiber in preparation for fusion splicing. The splicing process begins by preparing both fiber ends for fusion, which requires that all protective coating is removed or stripped from the ends of each fiber...
- RecoatingRecoatingRecoating is the process of restoring the primary coating to stripped optical fiber sections after fusion splicing. In the recoating process, the spliced fiber is restored to its original shape and strength, using a recoater. The stripped fiber section is recoated by filling a recoating resin,...
- Optical communicationOptical communicationOptical communication is any form of telecommunication that uses light as the transmission medium.An optical communication system consists of a transmitter, which encodes a message into an optical signal, a channel, which carries the signal to its destination, and a receiver, which reproduces the...
- Optical fiberOptical fiberAn optical fiber is a flexible, transparent fiber made of a pure glass not much wider than a human hair. It functions as a waveguide, or "light pipe", to transmit light between the two ends of the fiber. The field of applied science and engineering concerned with the design and application of...
- Fiber optic communications