Free-Space Multi-beam Optical Communication Terminal Design for Spacecraft

Abstract

Contemporary optical communication terminals are capable of higher data rates, over longer distances for less power compared to traditional radio communication terminals. As of writing, these terminals are almost exclusively single beam compatible. This thesis describes dedicated multi-beam terminal with COTS components. The design study used a custom model based on Fresnel propagation. The model showed that the “resolution” of the steering mechanisms can affect the system performance. The trade-offs showed that a high resolution Spatial Light Modulator together with a fast Micro-Mirror Array allows for both fast and accurate beam control. The duplex system placed the incoming and outgoing beams along the same path, resulting in the feedback loop only needing to track half of the beams. A new beam control algorithm was produced which can dynamically adjust according to the beam positions and locations. The transceiver was also designed with high performance fiber optic components.