Space-Based Optical Communication System Utilizing Fiber Optics.

摘要

The use of fiber optics to simplify the design of free-space laser communication systems is explored. The potential advantages of fiber optics within free-space optical communication systems are not widely recognized. The current generation of spaceborne optical communication systems relies on the use of bulk optics rigidly mounted to an optical bench to get light from the optical sources to the exit aperture or from the entrance aperture to the optical receiver. These designs are all very sensitive to thermal and mechanical perturbations as well as to the detailed dynamic characteristics of the host spacecraft. Optical fibers can provide the means to remotely locate the transmitter lasers, local oscillator (LO) lasers (in the case of a coherent system), and the receiver from the front-end optics. This allows flexibility in the mechanical design which can reduce the size, weight, and stability requirements of the overall system. This paper presents an overview of a fiber-based free-space lasercom system and contrasts this proposed technology to the present technology. Detailed design considerations concerning the issues of pointing, tracking, and receiver communication performance are presented. Other key areas such as efficient source-to-fiber coupling, isolation, transmitter power limitations, and acquisition are highlighted. Preliminary experimental results of our breadboard fiber-based coherent optical communication system are also presented. (rrh)