Technologies of the group Laser Components and Fibres


PREFORM FABRICATION

MCVD plant with lathe and control system.

The group primarily uses the MCVD process to produce the fibre preforms. The commercial MCVD system from the manufacturer Optacore was specially adapted to the group's research focus and offers the following options:

  • Dotands:
    • Passive: Ge, Al, P, F, B
    • Active: Rare-Earth ions (e.g. Er3+)
  • Doping concepts:
    • Chelate doping
    • In situ solution doping

In addition, the group has the capability to produce preforms using the stack-and-draw method.

CONTACT PERSON MCVD

FIBRE FABRICATION

Furnace in fiber drawing process.

In order to rejuvenate preforms into fibres, the group uses a 12 m high fibre drawing tower from the company Nextrom. This offers the following possibilities, which are used as part of the research focus:

  • Fibre types:
    • Step-index fibres (single-mode, multimode, polarisation-maintaining)
    • Laser active fibres, also in double-clad geometry
    • Multicore fibres
    • Photonic crystal fibres
  • Fibre diameters from 80 µm to 400 µm, production speed up to 400 m/min
  • Max. usable preform size: 1.5 m length and 50 mm diameter
  • Coating materials: acrylate, polyimide, silicone, option on metal, carbon
  • Systems for twisting and/or pressure control for stack-and-draw preforms
  • Extraction of rods (mm diameter)
  • Determination of tensile strength 100 kpsi at 125/250 µm fibre geometry

CONTACT PERSON FIBRE FABRICATION

Dipl.-Ing. (FH) Katharina Hausmann
Address
Callinstraße 36
30167 Hannover
Building
Room
232
Address
Callinstraße 36
30167 Hannover
Building
Room
232

CHARACTERISATION

View on a preform through a polariscope.

In order to characterise preforms and fibres, the group has the appropriate equipment and is always developing novel concepts as part of its research focus:

  • Polariscope
  • High-resolution microscopes
  • Low coherence interferometer for layer thickness measurement
  • Measuring station for high-resolution lifetime measurements
  • Preform refractive index profiler

In addition, the working group has access to external measuring systems such as Raman, NMR spectroscopy or EDX/ESMA.

CONTACT PERSONS CHARACTERISATION

Dipl.-Ing. (FH) Katharina Hausmann
Address
Callinstraße 36
30167 Hannover
Building
Room
232
Address
Callinstraße 36
30167 Hannover
Building
Room
232

OPTICAL THIN FILM TECHNOLOGIES

A woman in cleanroom clothing takes colourful, shimmering, coated optics from a coating machine. A woman in cleanroom clothing takes colourful, shimmering, coated optics from a coating machine. A woman in cleanroom clothing takes colourful, shimmering, coated optics from a coating machine.
Unloading of coated products from a deposition plant.

In the field of optical thin-film technology, research activities involve the use of:

  • complex coating systems for high-power laser optics,
  • in-situ measurement methods to control coating processes,
  • Ion-assisted conventional coating processes,
  • Ion sputtering technology (on more than ten coating systems).

A comprehensive infrastructure is available for the characterisation of the manufactured components, including equipment for the standard-compliant (ISO) determination of:

  • optical transfer properties,
  • scattering,
  • absorption and
  • laser-induced damage thresholds.

CONTACT PERSON THIN FILM TECHNOLOGIES

Prof. Dr. Detlev Ristau
Address
Callinstraße 36
30167 Hannover
Building
Room
225
Address
Callinstraße 36
30167 Hannover
Building
Room
225