The electricity was used for two centuries not only to power the world's industries, but also to spread the information across the Earth. Radio waves of the 19th century were followed by TV broadcasting , which all required more sophisticated electronics, and the electron tubes of the 1930's were replaced by smaller transistors in 1950's. The invention of semiconductor integrated circuits in 1959 by R. Kilby triggered a revolution in miniaturizing electronic circuits, with now millions of transistors on a single piece of silicon. This has enabled a massive increase of computational power, and allowed for streaming and processing of videos, which demand a lot of power. However, we are facing a problem: switching elements, i.e. the transistors, cannot be made arbitrary small, as they approach a size, where quantum effects become important. Furthermore, they cannot be made smaller due to production problems. By making transistors smaller, the electric signals that travel from one transistor to another get delayed and slowed down. This has nowadays slowed the operating rate, at which millions of transistors operate in unison, to a couple of GHz. This rate of switching the electric current through the integrated circuit and dense integration has resulted in huge increase of locally produced heat and temperatures of the chips are increased to the material limits. The ever increasing processing power is therefore blocked by the fundamental limits of electron transport in silicon. If any substantial advancement is to be made, a novel concept of signal and information processing is to be found. Yet, there is a new concept that could replace the electric integrated circuits: photonics or the science and engineering of light. The idea is to replace the flow of electrons in integrated circuits by the flow of photons in photonic integrated chips. Photons, like electrons, behave like particles, and they travel at the speed of light. Unlike electrons, photons do not exert force on each other and it is difficult to control their flow. Nowadays, photons are sent at a speed of light through optical fibres all over the globe, and have replaced the electrons in wire communications. The use of photonics has dramatically increased the amount of information that can be sent to any distant receiver. A typical photonic integrated circuit incorporates micrometer-sized lasers that send light via thin waveguides to light switches, detectors and other photonic elements. Most of today's integrated photonic circuits are made from silicon, exploiting the 50+ years of engineering. Silicon photonics promises to dramatically increase the computing power of microprocessors, which will use light instead of electricity. Yet, it is not quite clear if silicon photonics could support the explosive demand for data processing that is expected in the 21st century. At current pace, the required ICT energy demand will surpass the world total energy production within two decades.
LOGOS is not a mainstream photonics project. Instead, it will be the cornerstone of a new photonic technology based on self-assembled soft matter, likely to evolve into currently unforeseen, futuristic technologies. Unlike today’s photonic technologies based on hard matter that are energy consuming, use poisonous chemicals, precious metals, and producing large amounts of dangerous waste, LOGOS will exploit the room-temperature self-organisation of soft organic matter to develop functional photonic devices. This requires less production energy and reduces the carbon footprint due to the processing of materials at room temperature, uses environmentally friendly organic materials, and drastically reduces hundreds of production steps in silicon technology. This is likely to result in a huge reduction of chemical waste, as soft-matter devices can be both biodegradable and biocompatible.
