We have developed a novel low-cost electrostatically actuated 1x2 fiber switch which basically consists of two active components only, i.e. metalized movable fibers and fixed electrodes. With this set-up, a direct movement and, additionally, a self-alignment of the fibers is performed. In contrary to other MEMS designs no complex moving parts are necessary. It is possible to fabricate the switch with low-cost polymer techniques. Driving voltages below 60V and switching times below 8ms have been demonstrated with these polymer devices.
The optical fiber switch presented utilises electrostatic forces to move one incoming fiber with respect to the two outgoing fibers. Simultaneous application of the actuation voltage to the inlet fiber and the respective outlet fiber will pull both fibers into the same corner of the actuation chamber, where they settle in a perfect optical alignment.
During the last decade rapid prototyping has made a tremendous success in almost every branch of industrial fabrication. Almost every article of today’s life is pre-fabricated in a rapid process during its design. Functional rapid prototypes represent an increasing share, as they allow realistic functional tests of a component in an early stage of development.
MEMS technology is still at the beginning of the rapid prototyping aera. Up to now, only a few conventional techniques, like stereolithography, have been downscaled to create rapid microprototypes with a limited choice of materials and geometries. Rapid prototyping of silicon is completely out of reach today.
In this paper we propose a micro rapid prototyping concept for functional silicon microstructures. The process combines laser technology with standard processes of silicon microstructuring and has been evaluated with a metal-silicon layer system. First, noble metal is vapour deposited on top of a silicon wafer. The metal is subsequently structured with a laser, thus creating a mask, which can be transferred into the silicon by standard chemical etching procedures like KOH-etch. The advantage of this concept is that the time-consuming photomask generation is omitted completely, as the laser can be guided with CAD data. Moreover, the standard structuring process gives the opportunity to gain a microstructure with features equivalent to the final component.
With laser ablation and KOH-etch two process steps are being carried out subsequently, which are inevitably linked to each other. Depending on the energy of the laser irradiation the ablation performance changes and, with it, the minimal structure width and the thermal melting zone at the edges of the mask openings. If the energy density is too high the crystalline structure of the silicon is destroyed by heat transfer and heat conduction. Hereby the anisotropic etch resistance is lost, which influences the following KOH-etch process.
At the current state the process is monitored and optimised for different values of laser energy density. In this progress report the optimisation and the principal feasibility will be shown with simple micromechanic and microfluidic structures.