Title of Paper: Multi-Gigabit Data-rate Optical Communications Depicting LEO-to-GEO and GEO-to-Ground Links

Principal Author: Dr. Hamid Hemmati

Abstract: The goal of this AIST-funded task is to develop key components of the technology that will enable optical communications to meet the data delivery requirements of the EOS community. A systems engineering document that outlines the requirements followed by acquisition and tracking scenarios, and communication link analysis was completed. The link analysis identifies the telescope aperture sizes and the required beacon and transmit laser power. Both LEO-to-GEO and GEO-to-Ground links have been considered. The LEO-GEO link is considering a 1.24 Gbps data-rate link while the goal of the GEO-Ground link is 10 Giga-bit-per-sec (Gbps) in a single or four 2.5 Gbps channels.

The first year (of the two-year effort) focuses on communication link demonstration in the laboratory and detailed analysis and planning for acquisition, tracking and pointing. We are now developing the transmitter, receiver and optical subsystems that constitute the breadboard. Current emphasis is on a 2.5 Gbps link while the components are also being developed for a 10 Gbps data-rate link.

The breadboard utilizes a 13 cm diameter telescope as transmit aperture, simulating the LEO terminal. The receiver is a 30-cm all Silicon Carbide telescope which simulates the GEO terminal. The objective of the laboratory breadboard development is to demonstrate that the optical communications link could be established efficiently as predicted by the link analysis programs.

The second year of the effort would concentrate on acquisition. Tracking and pointing strategies and a demonstration of tracking between two moving platforms depicting a LEO-to-GEO link.