Laser stacks emitting short light pulses are ideally suited for medical and cosmetic applications. Developing enhanced, stable and reliable assembly processes, Jenoptik is reaching for higher energy densities and lower manufacturing costs. In this paper an improved technology for actively cooled QCW stacks is presented. Based on simulations and experimental data, the impacts on the laser stack performance are described and shown as power-current and thermal impedance plots. We show that the bar-to-bar pitch can be reduced from 1.7 mm to 1.2 mm without detrimental thermal effects for pulse durations up to 100 ms.
High-brightness fiber coupled laser modules are presented with output powers of more than 75W and electro optical
efficiencies of more than 45%. An ongoing lifetime test shows nearly 3000h reliable operation. A wavelength
stabilization using external gratings is shown with stable wavelength locking over a large temperature range. To combine
the output powers of the fiber coupled modules fiber combiners were used and powers in the 400 and 1000W range were
achieved for output fibers of 200 and 400μm, respectively.
Lasers for marking, direct application laser systems as well as high power solid state lasers require highly reliable, high
efficient and low cost laser diodes. Especially fiber lasers and direct diode systems have additionally the need for high
brightness. For a very long time either single emitter solutions with low brightness and costs or beam shaped bar
solutions with high brightness and high costs served those needs. Since roughly 2 years multiple single emitter solution
are more and more penetrating the market showing a high potential for serving all needs of a broad customer base.
Based on the 50W product introduced by the middle of 2009 we would like to show the design which is based on
qualified and highly stable single emitters.
For mounting FAC lenses to diode lasers a new technology is introduced. Solder jet ball bumping is demonstrated to
have the potential to replace conventional mounting technologies like adhesive bonding. The advantage of this method is
a thermally and mechanically stable connection of micro optics and laser without drawbacks of outgasing and sensitivity
The reached accuracy is within the range of one micrometer.
The industry of laser marking, direct application and solid state laser pumping requires highly reliable and highly
efficient laser diodes. In general, all applications demand improved brightness and temperature stability, and this by
decreasing costs per watt. Instead of increasing the cavity length, we demonstrate in this paper an increase of power
with standard cavity length with a clear focus of cost reduction and high efficiency. Improvements in the semiconductor
material and packaging enable higher power and higher operation temperature. This technology raised the efficiency by
6 % of 808 nm bar with 50 % filling factor and a resonator length of 1.5 mm.
Now, passively cooled diode lasers have reached nearly the performance of actively cooled ones. With this new design
new fiber coupling modules with high brightness and high operation temperature for air cooled systems can be
Miniaturized optical systems that couple light from broad area or trapezoid diode laser bars with cw powers up to 100 W
into fibers with core diameters between 50 μm and 100 μm have been developed and assembled on smart Direct-Copper-Bond (DCB) system platforms that incorporate active cooling structures as well as hermetic housing facilities. The
approach for a fast and flexible joining of the optical elements by a flux-free applied solder is to jet liquid solder spheres
onto joining geometries, thus enabling for creating complex shaped solder joint geometries with high accuracies.
The current-voltage characteristics of ITO/polymer film/Al or Au devices of poly(phenylene vinylene) (PPV) and a dialkoxy PPV copolymer can be fitted at high applied bias to a power law of the form J equals KV<SUP>m</SUP> where m increases with decreasing temperature, log(K) is proportional to m, and K is proportional to d<SUP>-(alpha</SUP> m) where d is the film thickness and (alpha) is a constant. (alpha) 2 and 1 for the Al and Au cathode devices respectively. Different single carrier space charge limited conduction (SCLC) theories, including either an exponential trap distribution or a hopping transport field and temperature dependent mobility, are used to try and explain this behavior. Both models are in good agreement with the general experimental results, but can also be criticized on a number of specific issues.Mixed SCLC models and the effect of dispersive transport are also explored. It is concluded that carrier mobility and trap measurements are required to distinguish between these models. To this end, initial trap measurements of ITO/PPV/Al devices using deep level transient spectroscopy (DLTS) are reported. Very deep positive carrier transport with emptying times > 4 minutes have been detected. The non-exponential DLTS transients have been successfully modeled on an isoelectronic trap level emptying to a Gaussian distribution of transport states, with a trap depth and density of 0.8eV and 4 by 10<SUP>16</SUP> cm<SUP>-3</SUP> respectively.