High precision approaches for active and passive alignment and assembly on optoelectronic micro
benches have been realized at Fraunhofer IZM for various material systems and different scales. The
alignment and reliable mounting of optical subcomponents such as semiconductor laser and photo
diodes, micro lenses and micro prisms require far higher mounting and alignment accuracies than for
micro-electronic parts. When connecting from silicon photonics chip level to single mode optical
fibers, even higher precisions are called for (typically < 100 nm). Alignment and assembly
commonly are performed on specialized lab equipment which needs manual operation, consuming a
lot of time, with less possibilities for automation.
To introduce a higher degree of automatized production, like it has become standard in large volume
electronics, one can choose either active or passive alignment processes - or possibly a combination
of both. In this article we will present examples of micro-optic benches and optical interconnections
that include alignment structures for passive alignment - where the accuracy lies in the components
to be assembled, and mounting takes place on a less accurate machine (“fit into place”). But there is
also a lot of progress on optical "pick, measure and place" machines that realize a flexible and fully
automated active alignment using vision systems and activated components of less cost, with
machine and process robustness for usability in industrial environments.
As connecting elements, passive optical components like optical fibers are commonly used. These
fragile and flexible elements pose additional challenges in secure picking, placing and fixing, at long
lengths vs. small diameters. A very recent and specific approach to use more robust plastic optical
fibers (POF) for very short and cost effective optical interconnects by means of wire bonding
machines will be presented.