SOI-based 2-D MEMS L-switching matrix for optical networking

Two-dimensional microelectromechanical system (2-D MEMS) optical switches have been widely demonstrated in research laboratories and in the industry. A novel switching architecture, the L-switching matrix, that decreases the most distance free space path length and the difference between the most and least distance paths while maintaining nonblocking port switching capacity has been proposed and demonstrated. Collimators with optimized beam waist are selected such that the insertion loss of the average beam path is the lowest. Larger beam waists are used to accommodate for the diffraction effects of the Gaussian beam of the most distance path. However, larger beam waists require larger mirror areas to avoid beam-clipping and losses due to angular misalignment are more acute. Therefore, having shorter absolute and relative path lengths will avoid the beam-clipping effects and increase the port-to-port loss uniformity of the optical switch. The unique architecture of the L-switching matrix which utilizes a double-sided mirror can theoretically increase the maximum port-count to 64×64 or decrease the current insertion loss of a 32×32 MEMS switch by 50%. Moreover, the L-switching matrix requires 25% less mirrors and electrodes than a conventional cross bar architecture. A fabrication process involving silicon-on-insulator (SOI) wafers has been defined to fabricate the double-sided mirrors used in the L-switching matrix.