Bulk silicon micromachining for MEMS in optical communication systems

Crystalline silicon has become more and more important for optical MEMS. The increased need of bandwidth in optical communication networks has led to a number of new optical MEMS devices such as moving-fibre and moving-waveguide switches, optical cross-connects, mirrors, resonators, optical benches and fibre alignment structures which are based on wet anisotropic micromachining techniques and deep reactive ion etching of single-crystal silicon. The excellent mechanical properties as well as the optical properties and orientation-dependent etching behaviour of crystalline silicon attract attention for reliable optical components based on surface micromachining, silicon-on-insulator, integrated optics and bulk micromachining. Anisotropic etching is especially useful for the batch fabrication of large opto-mechanical devices with sub-mum precision.