Laser Stack
Laser Stack

Stacks

Scheme

Laser diode stacks consists of vertically or horizontally arranged laser bars. Thus the overall power scales with the number of laser bars to power in the kW region.

Applications

  • Pumping of solid-state lasers
  • Material processing

Wavelength

  • 940 nm
  • other wavelengths are also possible

Chip technology

  • Semiconductor layers by means of MOVPE
  • Structuring of laser diodes
    • Projection lithography
    • Wet chemical etch procedures
    • Implantation
    • Contacts by evaporating and sputtering procedure
  • Thinning
  • Scribing, splitting, cleaving
  • Facet coating and passivation

Assembly

  • Soldering of bars on passive CuW heat sinks
  • Stacking of CuW heat sinks and fixing using AuSn solder suitable for extremely long lifetimes
  • Attaching of FAC lenses on the stack

Typical data

  • QCW operation tP = 1 ms f = 20 Hz
  • Single bar
    • Output power > 100 W with an aperture of 1.7 mm
    • Vertical far field with an FWHM of 14°
    • Efficiency close to 60%
    • [Publication, pdf]
  • Stack of 12 bars and FACs
    • Output power 1.2 kW
    • Simple and efficient coupling into fibres possible
      • Vertical divergence (>96% power level) < 7 mrad
      • Vertical beam parameter product < 60 mm mrad
      • Lateral divergence (>96% power level) < 220 mrad
      • Lateral beam parameter product < 90 mm mrad