2×2 torsion-mirror optical switch arrays with monolithically integrated fiber holding structures

Novel 2×2 torsion-mirror optical switch arrays with monolithically integrated fiber holding structures are fabricated using the mixed micromachining based on surface and bulk silicon microelectronics. Polysilicon micro-mirrors supported by suspended torsion beams are designed as the movable parts of the switches in the arrays. The mirrors are independently driven by electric force of applied bias to redirect the incident light in a free space. The electrostatic threshold voltages for driving the mirrors to achieve their ON-state are in the range of 190∼210 V and the minimum holding voltages for keeping the mirrors to be in their ON-state are found 55 V or so. The switching time and lifetime of the switches can reach less than 2 ms and 10⁶ at least, respectively. The fiber holding structures, which features self-fixing and self-positioning of optical fibers, are produced monolithically on the arrays using the same etching steps for forming the relevant cavities and grooves in the switch arrays.