The development of photonic technologies to speed up computing has taken two steps forward, following recent announcements demonstrating the use of photonics in both processing and data transfer.
Optalysys, a start-up company based in Cambridge England, has announced that, starting next month, its prototype optical processing system will be used in large-scale DNA sequence searches, saving up to 95 per cent of energy costs compared to conventional electronic methods, the company claims. in addition, IBM has announced that it has produced an integrated wavelength multiplexed silicon photonics chip, which will allow the bulk manufacturing of 100 Gbps optical transceivers.
Research into ways of boosting the speeds of both processors and interconnects is looking at many different technologies. Some use conventional silicon-based electronic technologies, such as FPGS as discussed in Robert Roe's article Will OpenCL open the gates for FPGAs?, while other avenues being explored include server on a chip and IBM's OpenPower initiative as discussed in Robert Roe's second article on Future processing technologies. More exotic -- and much longer term techniques such as quantum computing are also being explored as discussed in Quantum computing takes a step closer. Optical processing and silicon photonics are also longer term technologies, but research is overcoming the barriers to their practical implementation, as the recent announcements show.
Optalysys hopes optical processing will accelerate computation by performing processor-intensive tasks at much faster rates and with a significant reduction in energy consumption. The principle is similar in some ways to how a GPU is used to accelerate compute intensive tasks but the Optalyssys prototype is a desktop-sized system rather than a single card connected through PCIE.
The CEO of Optalysys, Dr Nick New, said: ‘Until now, meaningful optical processing technology has been impractical. Advancements in liquid crystal technology now permit numerical data to be dynamically entered into an optical system at high speeds and resolutions. Several additional breakthroughs by the Optalysys team have resulted in a patented lensless design which is easily aligned to within a few microns.’
The prototype demonstrates optical derivative functions – mathematical building blocks commonly used in complex engineering model simulations such as weather prediction and aerodynamic modelling. It also performs correlation pattern matching used in Big Data analysis such as DNA analysis and financial modelling.
The prototype achieves a processing speed equivalent to 320 Gigaflops and, because it uses light rather than electricity as the processing medium, it is much more energy efficient than classical processing devices.
The first project to utilise Optalysys technology starts next month in collaboration with The Genome Analysis Centre (TGAC) to build a genetic search system called GENESYS that will perform large-scale DNA sequence searches. The project has received £500,000 in funding from the UK Government agency, Innovate UK.
According to the chairman of the company, James Duez, Optalysys’s initial products will launch in 2017 and he expects them to achieve HPC-levels of performance up to an equivalent processing rate of 9 petaflops. He said that this was 'comparable to the 5th fastest computer in the world today. Following that we plan to pursue the design of larger systems capable of achieving multiple exaflops by 2020’.
IBM's current interests are more in the silicon photonics technology than in optical processing. The company's engineers have designed and tested a fully integrated wavelength multiplexed silicon photonics chip, which will soon enable manufacturing of 100 Gbps optical transceivers. This will allow datacentres to offer greater data rates and bandwidth for cloud computing and Big Data applications.
IBM’s silicon photonics chips uses four distinct colours of light travelling within an optical fibre to transmit data in and around a computing system. The critical point is that IBM has integrated the optical components side-by-side with electrical circuits on a single silicon chip using sub-100nm semiconductor technology. The ability to manufacture the components using conventional electronic industry techniques thus permits mass production and hence lower prices that will ensure more widespread commercial use of silicon photonics.
Most of the optical interconnect solutions employed within datacentres as of today are based upon vertical cavity surface emitting laser (VCSEL) technology, where the optical signals are transported via multimode optical fibre. Demands for increased distance and data rate between ports, due to cloud services for example, are driving the development of cost-effective single-mode optical interconnect technologies, which can overcome the bandwidth-distance limitations inherent to multimode VCSEL links.
IBM’s CMOS integrated nano-photonics technology combines the essential parts of an optical transceiver, both electrical and optical, monolithically on one silicon chip. IBM engineers have demonstrated a reference design, targeting datacentre interconnects with a range up to two kilometres.
