There are two major types of optical fibers: plastic material optical fibers (POF) and glass optical fibers – so, just how are optical fibers made?
1. Materials for optical fibers
Plastic material optical fibers are generally created for lights or decoration like fiber optic xmas trees. Also, they are used on brief range interaction programs like on automobiles and vessels. As a result of plastic material optical fiber’s higher attenuation, they have got very limited details carrying data transfer.
Once we talk about secondary coating line systems and fiber optic telecommunications, we really mean glass optical fibers. Glass optical fibers are mainly made from merged silica (90% at the very least). Other glass materials such as fluorozirconate and fluoroaluminate are also found in some specialized fibers.
2. Glass optical fiber manufacturing procedure
Before we begin talking how you can produce glass optical fibers, let’s first have a look at its cross section framework. optical fiber cross section is a circular framework composed of three layers within out.
A. The interior layer is called the core. This coating guides the light and stop light from escaping out with a trend known as total internal reflection. The core’s size is 9um for single mode fibers and 50um or 62.5um for multimode fibers.
B. The center layer is referred to as the cladding. It has 1% lower refractive index compared to the primary material. This distinction performs an essential part in total internal representation phenomenon. The cladding’s diameter is normally 125um.
C. The external layer is known as the coating. It is actually epoxy cured by uv light. This layer offers mechanical safety for that fiber and definitely makes the fiber flexible for handling. Without it coating coating, the FTTH cable production line will be very fragile as well as simple to break.
As a result of optical fiber’s severe tiny dimension, it is far from sensible to create it in a single step. 3 steps are needed as we explain listed below.
1. Preparing the fiber preform
Regular optical fibers are made by initially constructing a sizable-size preform, with a very carefully managed refractive directory profile. Only several countries including US have the capacity to make large volume, high quality fiber preforms.
This process to help make glass preform is called MOCVD (altered chemical substance vapor deposition).
In MCVD, a 40cm long hollow quartz pipe is fixed horizontally and rotated slowly on a special lathe. O2 is bubbled via solutions of silicon chloride (SiCl4), germanium chloride (GeCl4) and other chemicals. This precisely combined gasoline will then be injected in to the hollow pipe.
As the lathe transforms, a hydrogen burner torch is relocated up and down the outside of the pipe. The gases are heated up through the torch up to 1900 kelvins. This extreme heat triggers two chemical substance reactions to occur.
A. The silicon and germanium interact with o2, developing silicon dioxide (SiO2) and germanium dioxide (GeO2).
B. The silicon dioxide and germanium dioxide down payment within the pipe and fuse together to form glass.
The hydrogen burner will be traversed up and down the length of the tube to down payment the content evenly. After the torch has reached the end in the tube, this will make it introduced back to the starting of the pipe as well as the transferred contaminants are then dissolved to make a strong layer. This procedure is repeated until a sufficient amount of materials has been deposited.
2. Sketching fibers on a sketching tower.
The preform is then installed towards the top of the straight fiber sketching tower. The preforms is initially lowered in to a 2000 degrees Celsius furnace. Its tip gets melted till a molten glob drops down by gravity. The glob cools down and types a line because it drops down.
This starting strand will be drawn through a series of barrier covering cups and UV light curing ovens, finally on to a engine managed cylindrical fiber spool. The motor gradually pulls the fiber through the heated up preform. The created fiber size is exactly controlled with a laser beam micrometer. The running speed from the fiber drawing engine is approximately 15 meters/second. Approximately 20km of Fiber coloring machine can be wound on to a single spool.
3. Screening completed optical fibers
Telecom programs need very high quality glass optical fibers. The fiber’s mechanical and optical properties are then examined.
A. Tensile power: Fiber should withstand 100,000 (lb/square inch) stress
B. Fiber geometry: Checks fiber’s core, cladding and covering dimensions
A. Refractive directory profile: The most critical optical spec xxyjcw fiber’s details carrying bandwidth
B. Attenuation: Really crucial for long distance fiber optic links
C. Chromatic dispersion: Becomes more and more critical in high speed fiber optic telecom programs.