Individualized FAC on bottom tab subassemblies to minimize adhesive gap between emitter and optics II (Conference Presentation)

The quality of High Power Diode Laser (HPDL) systems highly depends on the assembly precision. Nowadays, neither the precision of the manipulation tools (step resolution < 10 nm) nor the measurement systems utilized in active alignment algorithms (alignment precision of ~50 nm) are the quality limiting factors but the bonding process is. This is due to the volumetric shrinkage of fast curing UV-adhesives in the curing process. The objective of this work is to minimize the absolute volumetric shrinkage of the UV curing adhesives between edge emitter and bottom tab so no significant misalignment while curing is expected. The approach was first described in the paper [SPIE 10086-28] and aims for minimizing the glue gap and therefore the amount of adhesive through combining active alignment of fast axis collimators (FAC) to edge emitter with a tolerance compensated individualized FAC on bottom tab subassembly in a fully automated production process. With less adhesive the absolute volumetric shrinkage is reduced. The expected benefits are the reduction of the misalignment through volumetric shrinkage and a 100% quality assessment without additional costs. Lens quality data such as smile, residual divergence and optical surface imperfections can be characterized. A permanent data collection provides feedback for all previous and following production systems and allows the improvement of the quality for the whole HPDL production chain. This paper presents the results gathered by implementing the individualized FAC on bottom tab process in an industrial production environment and compares it to the expected benefits to conventional HPDL production.