Osram mini laser bars offer exceptional brilliance

The output and beam parameters of the mini laser bars have been closely matched so that the powerful light beam, which leaves the small laser aperture at a defined angle, can be coupled into a small fibre core diameter with a restricted acceptance angle.

The mini laser bars have been optimised for fibre injection.

Sampling will start immediately and series production will commence in early 2010.

The brilliance of a laser is a measure of the output power per unit area and solid angle, defining how much light from a mini laser bar can be efficiently injected into a glass fibre.

The high brilliance of this laser bar has been achieved by the very large optical cavity (VLOC) epitaxial structure and proprietary mirror coating technology.

Dr Jorg Heerlein, head of laser product marketing at Osram Opto Semiconductors, said: 'Our new mini bars have a high optical output and efficiency, which enables us to offer tailor-made solutions for cost-effective fibre-coupled laser diodes.' Mini laser bars also combine the advantages of single emitters with those of classic 1cm bars.

They are cost effective, durable and can be adapted to meet the requirements of different applications thanks to their small size, according to the company.

In contrast to conventional fibre-coupled diode laser systems, the new bar structures allow more cost-effective beam-forming concepts to be used for fibre coupling.

The associated reduction in system costs is a major factor in making diode laser systems more attractive for direct material processing, particularly in comparison with alternative laser solutions.

Osram's brilliant mini laser bars are available in various application-specific product families, with fill factors of 10 per cent to 20 per cent and typical efficiencies of up to 65 per cent.

In addition to pumping fibre lasers, the laser bars are also used for direct micro-material processing, such as marking and micro-welding.

The brilliance of the mini laser bars is exemplified by the SPL BF series, which has a fill factor of 10 per cent and provides an output of 8W per emitter at an emitter width of 100um, with a slow-axis divergence of less than seven degrees (the value applies to 95 per cent output).

The maximum output compatible with long life is around 12W per 100um emitter.

With five emitters, the beam parameter product is 15mm x MRAD.

With the aid of simple optics, the light from several mini laser bars can be coupled into a fibre with a core diameter of 200um and a numerical aperture (NA) of 0.22.

In this way, outputs from the fibre in excess of 200W can be achieved.

Depending on customer requirements, a number of further designs and specifications can be produced on the basis of the new technology, according to the company.