Surrey Researchers Produce Landmark 40Gbit/S Silicon Optical Modulators
Tuesday 4 October 2011
Two researchers at the University of Surrey have recently demonstrated high extinction ratio 40Gbit/s modulation from two different designs of silicon optical modulator.
Until recently only one other all silicon optical modulator has been reported with data transmission at 40Gbit/s and that had just a 1dB extinction ratio (the power difference between the 1 and 0 data levels), making it impractical for real applications.
Two novel designs of silicon optical modulator, based upon carrier depletion have now been designed, fabricated and tested within the EPSRC funded UK Silicon Photonics programme, and the European FP7 funded HELIOS project.
New research has been led by Dr David Thomson and Dr Frederic Gardes from the Advanced Technology Institute at the University..
Both designs have demonstrated modulation at 40Gbit/s, with extinction ratios between 6dB and 10dB, a performance which opens the door to a whole host of applications.
The research effort invested into silicon photonics worldwide has dramatically increased over the previous decade, largely due to the bandwidth bottleneck imposed by electrical based interconnects that silicon photonics can overcome.
Silicon based photonics in particular offers the prospect of integrating electronics with photonics on the same substrate adding greater functionality, enhancing performance and lowering costs. The performance optical modulators formed in silicon has been ever increasing with many demonstrations of data rates around 10Git/s recently. The jump in data rate from 10Gbit/s to 40Gbit/s is, however, significant as it can allow more efficient utilisation of optical fibre channels, a decrease in the number of required channels and a 75% reduction in power consumption per bit of data, providing a much more environmentally friendly solution.
Both designs have been developed with fabrication simplicity in mind and allow self-aligned processes to be used in their manufacture. This will minimise performance variations and increase device yield in large scale fabrication. The work has recently been published in the optics express journals which can be found at the following links:
http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-19-12-11804
http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-19-12-11507
Professor Graham Reed who leads the Silicon Photonics Group at Surrey said “The development of faster and more efficient modulators in silicon is key to the future success of the silicon photonics field, and to commercial exploitation. I am absolutely delighted that my group have been able to contribute via the development of these two excellent devices, especially given the competitive natures of this field of research.”
Professor Ravi Silva, Director of the Advanced Technology Institute added “I am extremely proud to see that researchers in the ATI are producing world class devices. Given that several technology giants are active in the field of silicon photonics, it is a very significant achievement to have produced not just the most impressive device design in the field, but the two most impressive”.
