MCVD lab for optical fibre preform manufacturing

Glass soot deposition process in MCVD plant.

Modified Chemical Vapour Deposition (MCVD) is a highly versatile process for optical fibre preform manufacturing. As a pure gas phase process, the produced optical fibres feature high intrinsic purity, resulting in ultra-low optical losses. The process uses volatile precursors of the glass forming chemicals as SiCl4, GeCl4 and POCl3 which flow through a high-quality fused silica substrate tube, where the reaction is initiated via a traversing H2/O2 burner. The formed glass particles settle on the inside of the glass tube due to thermophoretic forces induced by the persisting temperature gradient. Suitable process management enables the deposition of highly precise and complex refractive index profiles.

For manufacturing of actively doped optical fibres, the MCVD set-up at HITec features a chelate doping system for evaporation of low vapour pressure metal- and rare earth compounds. The technique promotes high repeatability of the manufacturing process and precise control of actively doped optical fibres. In addition, the MCVD at HITec is equipped with a system for in-situ solution doping (SD) avoiding to dismount/reassemble of the process tube from the MCVD lathe, as required for standard active fiber production process.

Besides, the HITec lab holds an etching tower for cleaning/etching of glassware with HF (aq.).

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