Decreasing Size, Weight, and Power of Opto-Mechanical Assemblies Using Single-Crystal Silicon

Abstract

As small satellites and unmanned-aerial-vehicles (UAVs) continue to proliferate, there is a growing need to increase the capability of their payloads. These platforms are typically attractive because of their lower cost and shorter development timelines compared to traditional programs. For optical assemblies in particular, the cost and schedule constraints substantially limit an engineer's options with regard to high-performance opto-mechanical materials. This restricts the achievable performance of the overall system. In order to overcome this barrier, additional design options must be made available. While often used as an optical substrate, single-crystal silicon (SCSi) is not typically thought of as a structural material. However, it has excellent opto-mechanical properties such as a high stiffness to weight ratio, a low coefficient of thermal expansion, and high thermal conductivity. Because of this, ultra-stable, lightweight, and robust assemblies can be built by using SCSI as both the primary metering structure and as a substrate for optical elements. While the application space is very broad, this effort focuses on the design elements typically required for a notional laser communication terminal. The results demonstrate the successful design, analysis, fabrication, and assembly of a lasercom SCSI optical bench. Ultimately, this study establishes both the feasibility and utility of using SCSI in next generation low Size, Weight and Power (SWaP) optical payloads.