Levels of abstraction in computing systems and optical interconnection technology

The design of a computing machine takes place at several levels of abstraction ranging from materials and device engineering to system architecture to high-level software. This system of levels of abstraction enables the design problem to be broken down into manageable subproblems, much as in a procedural programming language. On the other hand, it makes difficult the introduction of novel concepts and technologies such as optoelectronic device planes (“smart pixels”), which do not readily fit in the existing scheme of things. We try to develop an understanding of this system of levels of abstraction, why and how it resists the introduction of optical technology, and how one can modify it so as to successfully house optical technology. We argue that in the near future, optoelectronic technology can be successfully introduced if: (i) changing technology or applications create a significant bottleneck in the existing system of levels of abstraction that can be removed by the introduction of optical technology (e.g. interconnections, memory access); (ii) special purpose applications involving very few levels of abstraction can be identified (e.g. sensing, image processing); (iii) it is possible to modify a few levels of abstraction above the level that optical technology is introduced, so that the optical technology is smoothly “grafted” to the existing system of levels of abstraction (e.g. modifying communications schemes or standards so as to match the capabilities of optical switching systems, employing parallel architectures to match the parallel flow of information generated by optical subsystems).