The manufacturing of optical fibers is a complex operation requiring a sequence of highly sophisticated processes.
First, a preform is fabricated. The preform is a glass cylinder which structure is identical to that of the final optical fiber. The preform itself is often fabricated in two steps:
-The core preform is fabricated either by the VAD (Vapor Axial Deposition) or the FCVD (Furnace Chemical Vapor Deposition) technology
-The cladding is then added with the Sand Technology.
This distinction enables to separate the fabrication of the more demanding core, where the light proper will be carried, from the fabrication of the less optically critical cladding.
The preform is then drawn in a fiber drawing tower. At the top of the tower, the preform is progressively introduced in a furnace where it melts and the fiber is drawn with the internal structure identical to that of the preform. Further down the tower, where the glass has reached a lower temperature, the fiber is coated for protection from the environment.
The final steps of the manufacturing are a series of measurement and characterization of the fiber. These are essential to ensure the high quality of the product and the consistency of the production.