Laser based joining technologies for optical assemblies overcome the limitations of standard fixation technologies such as adhesive or wafer level bonding. By applying the laser energy locally and for a limited time these technologies enable for higher stability of optical joints as well as additional functionality. Working without intermediate layers laser splicing creates highly stable transparent joints that are suitable for the transmission of high power, e.g. in fiber laser assemblies. In contrast, laser beam soldering of optical components as an alternative with a metallic intermediate layer is non-transparent, but creates flexible and stress-compensating joints as well as thermal and electrical interconnects.