Miniaturization is not the only feature that is expected from modern microsystems. In addition to being small enough, today's systems are required to be highly integrable to be able to solve complex tasks including signal evaluation and the active readjustment of their own functions. To meet these demands, scientists of the Karlsruhe Institute of Technology have developed a novel modular solution for optical microsystems: In a hybrid way, modules of different functions are combined via precisely defined interfaces into an overall system. To realize active optical microsystems, commercial microactuators are connected via a platform with a micro-optical bench and are then provided with the data logic. Micro-optical benches which, just like micro-actuators, are basic components of the overall system are manufactured at KIT using the LIGA technology. High-precision plastic structures can be reproduced at low cost by means of commercial plastic replication techniques.The structures obtained that way serve as high-precision mountings holding and fixing optically tempered glass components in a position that is exactly defined to ensure a smooth operation of the overall system. This novel method allows a time- and cost-efficient automated assembly of the micro-optical system. The microoptical bench is connected via a joint adjustable connecting element with the adequate microactuator unit. The system thus is suited for a variety of uses reaching from simple interferometers for spectroscopic measurements to DQPSK modulators. The picture displays a modular microsystem by example of an interferometer with a piezoactuator (left) and an inchworm actuator (right). A micro-optical bench with glass components is shown in the foreground. The Institute for Microstructure Technology is looking for partners for development of optimized systems that can be manufactured in series for different applications..