  Numerous quantum technologies make use of a microgravity environment e.g. in
space. Operating in this extreme environment makes high demands on the
experiment and especially the laser system regarding miniaturization and power
consumption as well as mechanical and thermal stability. In our systems,
optical modules consisting of ZERODUR based optical benches with free-space
optics are combined with fiber components. Suitability of the technology has
been demonstrated in the successful sounding rocket missions FOKUS, KALEXUS and
MAIUS-1. Here, we report on our toolkit for stable optical benches including
mounts, fixed and adjustable mirrors as well as polarization maintaining fiber
collimators and couplers made from ZERODUR. As an example, we present the
optical modules for the scientific rocket payload of MAIUS-2, a quantum gas
experiment performing dual-species atom interferometry with Bose-Einstein
condensates. The modules are used on the one hand to stabilize the laser
frequencies and on the other hand to distribute, overlap and switch the laser
beams. This includes the overlap and joint fiber coupling of beams at 767nm and
780nm in the same polarization state to cool and manipulate atoms of both
species simultaneously. Future projects include the development of a platform
for experiments with cold atoms onboard the International Space Station. The
laser system again involves ZERODUR based optical benches in conjunction with
fiber optical components. The experiment is planned as multi-user facility and
currently in the design phase. The next step is to build the training, test and
flight hardware.
