Microelectronics and photonics have traditionally been considered as non-interacting disciplines. While they sometimes share common underpinning materials systems or fabrication technologies, whenever the need has arisen to integrate, say photonics devices with microelectronic control, the problem has been addressed very much at the macro-scale, integrating discrete "blocks" with minimal interdependence. As dimensions reduce and complexity increases towards the realisation of nano-technologies, that situation has to change. At the heart of this project is a radical shift of perspective required as we move into a regime where systems comprising photonics and microelectronics can no longer be treated via block integration, but where multiple interactions between the optical and electronic functions have to be considered. This opens up exciting new physics and engineering challenges offering the prospect of a revolution in instrumentation.

Advancement of optical systems and instrumentation into the micro domain brings with it many new opportunities but at the same time significant technical challenges. Operation at the micro-scale can enable very high speeds and power densities to be achieved, in substantially lower cost, smaller footprint and lower power systems than is the case with current macro-scale technology. In the same way that microelectronics and diode lasers have revolutionised linear applications, combined micro-optical technologies are poised to bring techniques thus far confined to specialist laboratories into the realm of widespread application. Instrumentation for biomedical synthesis & analysis, environmental monitoring and materials science can all benefit greatly from the wider availability of the techniques that this technology can deliver.

Key to enabling the development of these new applications is a thorough understanding of the problems and techniques involved in the co-design and integration of often highly non-linear and heterogeneous technologies into a single platform. A fundamental challenge is the marrying of tools and techniques borne of very different disciplines (micro-electronics, optics, micro-systems, fluidics) where knowledge and cross-working mechanisms have not been established. Only by developing common problem framing, understanding and cooperation across disciplines can these new technologies be developed.
Fundamental to the project will be the change to a research mode in which the traditional engineering aspects of device design will be integrated with the understanding of the physical processes involved in the direct integration of electronics, photonics and the "end use" environment. The initiative will thus lead to a new "total research" approach to the challenges set in full system and instrumentation integration. We envisage that a thorough understanding of the fundamental physical processes taking place in integrated devices will lead to the development of novel modelling methods and design tools in which all relevant parameters are considered. From this bed rock of understanding full systems engineering can be considered leading to system implementation.

As an exemplary application of the long term research project expected to flow from the initiative, we consider the intimate integration of micro-optics, sources, electronics and biological media. We already have the capability to produce these "blocks" independently but for practical applications these must be integrated. Techniques such as "flip-chip" mounting allow drive electronics to be mounted directly behind each emitter. However, if the devices are to be used at high speed (sub nanosecond for fluorescence lifetime measurements for example) the direct interaction between the electronics, photonics and sample medium becomes crucial. To add to this challenge the optical output may be coupled into a biological or chemical sample under micro-fluidic control through micro-optical elements controlled by MEMS technology. Under this initiative, the interaction between these many disciplines will be developed such that all aspects can be optimised for collective performance. Such a truly integrated platform technology has applications ranging from cell sorting through to the examination of fluidic and phase interfaces via miniature confocal techniques.