SBIR-STTR Award

Current beam steering systems rely on optical pointing systems that are verycomplex, costly, and too large for most aircraft applications. We propose todevelop programmable reflective phase modulator arrays based on MEMS(Micro-Electro-Mechanical Systems) technology that are smaller, lighter,faster, more area efficient, and less prone to vibrational oscillations (robustto operate in a dynamic flight environment). Construction and materials of MEMS reflector arrays are relatively independent of wavelength used, and canwithstand high power exposures, since actuation mechanisms and low-cost bulkmaterials are isolated from the beams. A unique feature of our MEMS designs isthat it solves phased array addressing issues for 2D-arrays. Our MEMS deviceswould require only 2N lines (instead of N2) to individually program eachmicroreflector in a NxN array so that larger arrays can be built. This canpotentially result in a much more compact, monolithic solution as compared toorthogonally oriented 1D-arrays.To develop these scaleable designs we have a team of technologists with strongbackground in MEMS at NCSU, micro-optics, mechanics and optoelectronicpackaging at NIPT. As a result of the collaborative effort, the MEMStechnology developed at NCSU will be transferred to industry via NIPT. SinceMEMS technology is compatible with microelectronics and micro-opticstechnology, future systems can be compactly packaged for airborne applications. The goal is to eventually replace the current large and complex mirroredgimbal systems in use today with small, low cost systems that can be internallyor conformally mounted in an aircraft.

Current beam steerers rely on optical systems that are complex, costly, and excessively large for most aircraft applications. We propose to combine scaleable fabrication technologies to construct a prototype MEMS-based programmable beam steerer, with >90% fillfactor and optical efficiency. During the course of Phase I project, we demonstrated novel staking technologies to bond and vertically interconnect thinned MEMS dice (25 microns thick) with CMOS dice containing 2-D arrays of individually addressable driver circuits. The key technologies necessary to achieve this hybrid integration of mixed technlogy devices, such as chem-mechanical die/wafer thinning, vertical through-the-chip interconnection, and tiling were demonstrated. In Phase II, we will combine these technolgies with system concepts and technologies which will be demonstrated by the completion of Phase I to fabricate two prototypes: a) reflective beam steering device that will deomonstrate the feasibility of constructing integrated MEMS/VLSI devices with high optical througput andb) transmissive optical system that will allow on-axis adressing. A novel voltage-division driving scheme will also be implemented to dramatically reduce the number of addresing lines. The result will be scaleable system deomstrations that will ay the apth toward productization of Hybrid VLSI-MEMS Systems.

Keywords:
3-D STACKING MEMS VLSI-MEMS MICRO MIRRORS OPTICAL BEAM STEERING PROGRAMMABLE DIFFRACTIVE OPTICS