Mikrotechnisch hergestellte strahlteileraufnahme zur verwendung in einem optischen gyroskop

In order to detect the rotation rate with optical gyroscopes, a laser beam must circulate. In the developed miniaturized concept, this is to be realized by micro mirrors and a beam splitter. The concept is based on a two-beam interferometer readout technique. In this concept, the laser beam entering the system is divided by a beam splitter. The two partial beams strike two mirrors in opposite directions. They are reflected back to the beam splitter and onto a detector. The micro mirrors and also the mount of the beam splitter are produced by a KOH etching process. The {111} crystal planes released by the etching process have an angle of 54.74 ° to the (100) wafer surface. However, the beam splitter is a cube whose adjacent surfaces enclose an angle of 90° and which cannot simultaneously lie on the etched {111} facets with two surfaces. Thus its position and orientation are not well defined. In this work we have therefore used two wafers etched with different opening widths which are bonded on top of each other. Thereby, the beam splitter can rest on four edges and its position and orientation are precisely defined. However, during alignment a displacement error between the wafers can occur. An already produced beam splitter mount showed displacements of about 33 μm. This leads to a tilting of the beam splitter of approximately 1°. By optimizing the alignment in the bonding process reliable production with significantly reduced displacements will be possible.