Integration techniques of micro-optical components for miniaturized optomechanical switches

Novel concepts have been developed for miniaturized fiber optic switches. They are based on transmittive microoptical components. Here, beam deflection is achieved by moving microprisms or microlenses with the use of miniaturized actuators, mainly piezoelectric actuators. The deflected beam is directed to a microlens array where each of the lenslets couples the beam into one of the output fibers. The latter are also used as a regular army (fibers embedded in V-grooves in silicon). Such miniaturized switches can be realized with quite good optical parameters (insertion loss, cross talk), and also short switching time in the order of 1 ms. For prototype fabrication and future production of such switches integration methods of the microoptical components and the actuators play an important role. In the case that all components are adjusted and fixed separately a rather complex procedure and equipment is required and a special optomechanical design must be used to ensure sufficient system stability. In order to decrease considerably the effort for system integration we tested several approaches for building at first certain subassemblies. This was especially successful for the lens array/fiber array integration as the most critical in the switch configuration. By using a lens array substrate thickness slightly smaller than the lenslet focal length we were able to fix the fiber array by gluing directly to the substrate surface opposite to the lenslet surface. We also started to integrate other optical functions, such as deflection and collimation into one quasimonolithic component by replication techniques. Here, both microprism and microlens structures have been replicated onto SELFOC microlenses.