An increase in the performance of micro-optic beam shaping resulted in diode laser modules with more than 400W out
of 200 μm fibre based on Broad Area Laser Bars (BALB). The brightness of a 400 W laser module opened the door for
new applications in material processing such as temper marking of stainless steel and metal sheet cutting.
Further improvements of the light sources and the beam shaping for BALB's have increased the efficiency of the laser
Therefore we present an output power of 1200 W out of a 200 μm fibre (0.22 NA). This is achieved by further
sophistication of the coupling technique and four wavelength coupling. The beam parameter product is still 22
mm*mrad with a power density of 3800 kW/cm<sup>2</sup> if focussed to a 200 μm spot. Furthermore, each of the four
wavelength modules are separately exchangeable and checkable.
The availability of a top-hat profile out of the fibre proves itself to be advantageous compared to the traditional
Gaussian beam profiles of fibre, solid-state and gas lasers. This leads to excellent laser cutting results with extremely
small cutting kerfs down to 200 μm and very plane cutting edges. Process speeds rise up to more than 10 m/min i.e. for
thin sheet stainless steel or titanium. In the near future, 600 W out of 200 μm based on BALB's with a beam compressor
is possible. With wavelength coupling, power levels with up to 2 kW out of 200 μm fibre will be reached. This will
result in a power density of more than 6 MW/cm<sup>2</sup>.
Laser diodes and diode laser bars are key components in high power semiconductor lasers and solid state laser systems.
During manufacture, the assembly of the fast axis collimation (FAC) lens is a crucial step. The goal of our activities is to
design an automated assembly system for high volume production. In this paper the results of an intermediate milestone
will be reported: a demonstration system was designed, realized and tested to prove the feasibility of all of the system
components and process features. The demonstration system consists of a high precision handling system, metrology for
process feedback, a powerful digital image processing system and tooling for glue dispensing, UV curing and laser
operation. The system components as well as their interaction with each other were tested in an experimental system in
order to glean design knowledge for the fully automated assembly system. The adjustment of the FAC lens is performed
by a series of predefined steps monitored by two cameras concurrently imaging the far field and the near field intensity
distributions. Feedback from these cameras processed by a powerful and efficient image processing algorithm control a
five axis precision motion system to optimize the fast axis collimation of the laser beam. Automated cementing of the
FAC to the diode bar completes the process. The presentation will show the system concept, the algorithm of the
adjustment as well as experimental results. A critical discussion of the results will close the talk.
So far, diode laser systems could not compete against CO<sub>2</sub>-lasers or DPSSL in industrial applications like marking or
cutting due to their lower brightness. Recent developments in high-brightness diode laser bars and beam forming
systems with micro-optics have led to new direct diode laser applications.
LIMO presents 400W output from a 200μm core fibre with an NA of 0.22 at one wavelength. This is achieved via the
combination of newly designed laser diode bars on passive heat sinks coupled with optimized micro-optical beam
shaping. The laser is water cooled with a housing size of 375mm x 265mm x 70mm.
The applications for such diode laser modules are mainly in direct marking, cutting and welding of metals and other
materials, but improved pumping of fibre lasers and amplifiers is also possible. The small spot size leads to extremely
high intensities and therefore high welding speeds in cw operation. For comparison: The M<sup>2</sup> of the fibre output is 70,
which gives a comparable beam parameter product (22mm*mrad) to that of a CO<sub>2</sub> laser with a M<sup>2</sup> of 7 because of the
Many metals have a good absorption within the wavelength range of the laser diodes (NIR, 808nm to 980nm), which
permits the cutting of thin sheets of aluminium or steel with a 200W version of this laser. First welding tests show
reduced splatters and pores owing to the optimized process behaviour in cw operation with short wavelengths.
The availability of a top-hat profile proves itself to be advantageous compared to the traditional Gaussian beam profiles
of fibre, solid-state and gas lasers in that the laser energy is evenly distributed over the working area.
For the future, we can announce an increase of the output power up to 1200W out of a 200μm fibre (0.22 NA). This will
be achieved by further sophistication and optimisation of the coupling technique and the coupling of three wavelengths.
The beam parameter product will then remain at 22mm*mrad with a power density of 3.8 MW/cm<sup>2</sup> if focussed to a
200µm spot. This leads to excellent laser cutting results with extremely small cutting kerfs down to 200μm and very
plane cutting edges. Process speeds rise up to more than 10m/min i.e. for thin sheets of stainless steel or titanium.
We present new developed high power diode laser modules which are performing at outstanding brightness and their
applications. The combination of recently designed laser diode bars on passive heat sinks and optimized micro-optics
results to laser modules up to 50W out of a 100μm fibre with a 0.22 NA at one single wavelength based on broad area
laser bars (BALB) and up to 50W out of 50μm fibre with a 0.22 NA based on single-mode emitter array laser (SEAL)
bars. The fibre coupled systems are based on diode lasers with a collimated beam of superior beam data, namely < 10
mm x 10 mm beam diameter (FW1/e<sup>2</sup>) and < 2mrad x 2mrad divergence (FW1/e<sup>2</sup>). Such free beam diode lasers deliver
30 W or 60 W output power.
The applications for such laser diode modules varies from direct marking, cutting and welding of metals and other
materials up to pumping of fibre lasers and amplifiers. Marking speed with up to 30mm/s on stainless steel was
observed with 20W laser power and 50&mgr;m fibre with a conventional marking setup. Cutting speed of about 1m/min of
0.2mm Kovar sheet was shown with a diode laser module with 50W laser power from a 100&mgr;m fibre.