Optical satellite networks

With high-speed space optical crosslink being a reality, the construction of an optical satellite network as part of a larger integrated space-terrestrial network is now feasible. This paper explores the architecture implications of the invention of such a radical technology building block. Not only can the satellite network performance and cost undergo quantum-leap improvements but also such a network can have profound transforming effects on space system architectures and data network user applications.

I. Introduction

This paper builds on the premise that optical space communication at very high rates ( 10 Gb/s) between satellites is now feasible [1] [2]– [16]. It is reasonable to believe as more space packages are built and extensive on-orbit-operation experience develops in the next few years, the cost of high-rate optical crosslinks will be substantially lower than their microwave functional equivalent. A natural next step with such a powerful enabling technology is the realization of an optical satellite network of global extent. This optical satellite network can in turn revolutionalize space system architectures that may use the network as a critical subsystem. Examples of these space systems include those offering communication services or remote sensing. This paper summarizes briefly the state-of-the-art of optical crosslink technology, examines architectures (from the physical layer to the application layer) that combine other technologies to form an integrated space and terrestrial network, and finally explores the space of possible revolution in network performance and applications that are enabled by such a key technology innovation.