MEMS free-space fiber optic switches

In this dissertation, novel MEMS (micro-electro-mechanical systems) free-space fiber optic switches with fast switching time and low insertion loss are investigated. Fiber optic switches are widely used in optical fiber communication systems to reconfigure the network and/or increase system reliability. Since switches introduce additional optical losses, fiber optic switches should be designed to minimize the insertion loss. Low optical insertion loss and low crosstalk are two of the most important requirements for optical switches. Fiber optic switches can be realized by either free-space approach or waveguide approach. In general, opto-mechanical switches (free-space switches) provide the lowest insertion loss and crosstalk among all optical switches. However, conventional opto-mechanical switches are bulky, slow, and expensive. On the other hand, free-space fiber optic switches realized by MEMS technology can be made in compact, light weight and potentially low-cost.; In addition, bulk-micromachined silicon submount has been developed for the MEMS switches. The submount is designed to accommodate the surface-micromachined switching devices, micro lenses and optical fibers. This new hybrid-packaging method is used to minimize active optical alignment between the mirror chip and optical fibers to reduce the packaging cost. Sub-millisecond switching times have been achieved using the torsion mirror based switches. MEMS free-space fiber optic switches demonstrate a very strong mechanical property and are able to operate at an external vibration of up to 100g.