Integration of deformable mirror devices with optical fibers and waveguides

摘要

ble Mirror Devices (DMDs) have been under development at Texas Instruments for several years, primarily as spatial light modulators for free-space optical applications such as analog phase modulation and digital projection imaging. A DMD consists of one or more electrostatically deflectable micromechanical aluminum mirror elements, including both micromirrors suspended from thin flexible hinges and membranes. These devices are fabricated using low temperature silicon-compatible semiconductor processing techniques, and thus can be monolithically fabricated over any addressing circuitry. In the last few years DMDs have been integrated into optical fiber switching systems, and efforts are underway to integrate them as routing switches onto optical waveguides. The DMDs used for optical fiber switching are torsion-hinged devices similar to those used for projection imaging. These devices have been integrated with multimode fibers to construct a 4 $MUL 4 multimode optical fiber cross-bar switch with a 19 dB optical (80:1) extinction ratio for all 16 channels. Extinction ratios of 73 dB optical (20 $MUL 10$+6$/) have been achieved for single point single mode switches. The waveguide switches currently under development are deformable membranes which are monolithically fabricated on silicon wafers with phosphosilicate glass (PSG) waveguide directional couplers to form optical time delay path selection switches. In this paper we describe the fabrication of deformable mirrors, their integration with optical fibers and waveguides, and the resulting system performance.