A major area of research activity at the ORC and in the worldwide photonics community is the exploitation of the optical fibre, not simply as a passive waveguide, but as a medium to directly modulate, generate, or otherwise manipulate light. As a result of this versatility, fibres form key components of systems in almost any applications that use light.
In parallel with these breakthroughs in photonics, the computer and microelectronics industries have seen exponential growth every 18 months since the 1960's of the performance to price ratio of transistors on CPU and DRAM chips. This is equally matched with improvements in optoelectronic components such as the visible lasers used in DVD players, and the infrared laser diodes used to generate and modulate light for data communications in optical fibres. The crystalline semiconductors upon which all microelectronics are based, namely silicon, germanium, gallium arsenide and many others, are familiar to almost every scientist and engineer.
The advanced technological fields represented by silica glass based optical fibres and microelectronics based on planar chips fabricated by lithography, are typically integrated to create communication network systems. Integration can be achieved by using intermediate optics and packaging. However, it is preferable to avoid having to transform in-fibre photonic signals to chip-based electronic signals due to the complexity (and therefore high cost) of having to use heterogeneous, discrete optoelectronic components. Indeed, the ultimate vision would be a purely fibre based system.
We have developed and patented an innovative technique that takes a significant step towards this goal. Our technique allows us to fabricate crystalline semiconductor structures made from silicon and germanium directly inside the optical fibre itself. This technique utilises a deposition process similar to that used for modern planar electronic devices, opening up the possibility for directly combining the light guiding capabilities of optical fibres with the exceptional capabilities of semiconductors for manipulating light and electrons. Advanced technological applications demand high performance devices, which in turn require exceptional materials. In close collaboration with Dr Anna Peacock group which focuses on nonlinear semiconductor fibre devices, our efforts develop the fundamental materials research necessary to move this innovation beyond the laboratory to next-generation photonic devices and systems.