Raw materials

By partnering with LEONI you not only benefit from support along the entire value chain but also from the usage of ultra pure fused silica materials.

SQ Fused Silica

LEONI offers ultra pure fused silica in 5 quality grades which can be adjusted to individual customer needs. SQ Fused Silica is specifically designed for the use in optical and photonic devices in the fiber optic, semiconductor and display technology industries, as well as for optical applications and laser applications.

SQ Fused Silica offer an optical application range from DUV to NIR and show extremely low fluorescence and high stability under high-energy UV and laser radiation.


Highly pure fused silica materials in combination with customer specifications makes LEONI unique to produce high-quality preforms for the manufacturing and application of high-performance special fibers and standard fibers. We are able to make adjustments to the required waveguide design based on your specific needs whether you goal is to achieve transmission of high data rates or high power laser transmission.

Process Technology 
The first step is to choose the appropriate core material (either undoped fused silica with high or low OH content from LEONI's own raw material production or direct coating of doped fused silica).

In the next step, the waveguide preform is either produced with LEONI's own MCVD process for graded-index and step-index fibers or with a PBVD process for large core step-index fibers.


LEONI can produce three types of fused silica rod

  • SQ fused silica rods:
    • Made for applications in the UV/VIS range
    • High OH concentration
  • J-plasil fused silica rods:
    • Made for applications in the VIS to IR range
    • Low OH concentration
  • Special dopings, like BDSR:
    • Specific applications can be supported by various doping materials


LEONI uses ultra pure fused silica to produce tubes for special fibers, preforms and optical components. There is a wide range of applications for tubes, including industrial and medical applications as well as the manufacturing of photonic crystal fibers or combiners in high-power laser transmission.

LEONI offers fused silica tubes in different sizes and dopings: From undoped fused silica tubes to fluorine-doped fused silica tubes and as individual preform designs. 


Fiber Optics

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