j-fiber Process technologies

For innovative fiber optics solutions in data communications and a wide range of specialty applications

At the Jena facility, j-fiber have established a unique center of excellence using versatile process technologies including:

  • MCVD processes (Modified Chemical Vapor Deposition)
  • POVD processes (Plasma Outside Vapor Deposition)

The particular combination of the process technologies enables making fiber optic products and services, individually adjusted to the specific needs of our customers and the intended applications: from optical elements for laser applications to customized preform designs for large-core step-index fibers.


MCVD preform manufacturing process

This process involves the production of Fused Silica from gaseous constituents. The generated silica structure has the high purity required for data transmission –, which is not achieved by any other kind of manufacturing process. During MCVD, a rotating Fused Silica tube is heated over a flame, and a gas mixture of silicon tetrachloride, germanium tetrachloride and various gases is fed through it. These components chemically react forming small glass particles. Layer by layer, the glass is gradually deposited and fused onto the inner surface of the tube.

Fiber drawing technology

The completed preform is prepared for the drawing process in our in-house drawing towers. This involves the preform being secured to the top of the tower and then heated in a furnace to over 2,000 °C. The drawing process starts with a first silica droplet. The material tapers more and more and is finally, after threading through all apertures of the tower, drawn to the size of a hair's breadth. During this process the fiber cools down to room temperature. Depending on the target fiber diameter, a preform can yield many kilometers of fiber. To protect the silica fiber, it is coated with a dual-layer acrylate coating during drawing. The coating protects the fiber against environmental influences making the fiber processable for cabling. The fiber has now achieved its characteristic diameter of 0.25 mm (or alternatively 0.5 mm). Once wound onto reels, the fiber is sent to quality control.