Mashanovich et al. demonstrated for the first time, low loss propagation through SOI waveguides at the wavelength as long as 3.4 microns. In their Optics Express paper they reported losses of 0.6-0.7 dB/cm for SIlicon-on-Insulator (SOI) waveguides and 3.9 dB/cm for Silicon on Porous Silicon (SiPSi) waveguides. More on these results can be found at:

mid-infrared SOI and Sipsi waveguides demonstrated

Xia Chen received his BEng and PhD degrees in electronic engineering from the Chinese University of Hong Kong (CUHK), in 2006 and 2010, respectively. Between March and June 2010, he was a visiting researcher at the Australian National University and he later worked as a postdoctoral fellow at the CUHK. Xia has been recently awarded a Newton International Fellowship by the Royal Society, UK to work at the University of Surrey. His recent research focuses on waveguide grating couplers for fiber-chip coupling and silicon-based integrated devices for communications systems.

Xia (kenneth) chen joins the group

The 8th Group IV Photonics conference took place at the Royal Society in London from 14 to 16 September 2011. Last year, the Royal Society celebrated the 350th anniversary and and it is the oldest scientific academy in the world. The conference took place at a fantastic venue in central London which houses Newton original manuscripts amongst other things. Our group had 6 oral and 1 poster presentation on 40 Gbps modulators in silicon, novel (DE)MUX, eraseable Bragg gratings, QCSE modulation at 1.3 um, and mid-IR silicon devices. The conference chairs were Prof. Graham T. Reed from the University of Surrey, UK and Dr Jean-Marc Fedelli from CEA-Leti, France.

Graham reed chaired group iv photonics conference:
14-16 september 2011, The royal society, london

G Mashanovich ©

G Mashanovich ©

G Mashanovich ©

A £5 Million UK Silicon Photonics programme led by Surrey is now a part of a cluster of European silicon photonics R&D projects ( The projects are funded by European and national funding mechanisms. The European silicon photonics projects collaborate on dissemination and training activities, and on knowledge and technology transfer from R&D to industry.

european silicon photonics cluster

The Silicon Photonics summer school is co-organised by two major research consortia, UK Silicon Photonics (UKSP) and HELIOS. Furthermore, the event is co-located with the Summer School of the Erasmus Mundus Master of Science in Photonics (EMMP), which ensures the attendance of a large number of excellent external speakers. The UKSP/HELIOS Silicon Photonics Summer School is aimed at Masters and PhD-level students. The speakers will provide an accessible introduction to their respective fields as well as presenting their latest research results. More information on:

silicon photonics summer school: 3-8 july 2011, st andrews

The August issue of Nature Photonics had a special focus on Silicon Photonics. Graham Reed, Goran Mashanovich, Frederic Gardes and David Thomson, authored a review article on optical modulators in silicon. Optical modulator is a crucial device for future electronic/photonics integrated circuits. Unfortunately, silicon does not exhibit a linear electro-optical effect (the Pockels effect) due to its centrosymmetric crystal structure, thus making optical modulators in silicon difficult to realise. However, due to the extensive research effort of several groups in the world, including the Silicon Photonics Group at Surrey, optical modulators in silicon have been improved dramatically in recent years, with a notable increase in bandwidth from the megahertz to the multigigahertz regime in just over half a decade. Our paper in Nature Photonics discusses the techniques that have been (and will continue to be) used to implement silicon optical modulators, and also provides an outlook for the future. The paper is available at

review paper published in nature photonics

David Thomson et al. published a new design of high speed carrier depletion silicon optical modulator which features the use of a self-aligned fabrication process to form the pn junction. The positioning of the junction within the waveguide is problematic in reality due to tolerances of process tools. In this new design, no strict alignment of the junction is required, since a self-aligned process is used, thus enabling easier fabrication, fewer performance variations and a higher yield. Modulation data rate of 10 Gb/s with up to 6dB of modulation depth has been achieved (Optics Express, vol. 18, 19064-19069, 2010). The work has been performed as a part of EU FP7 project HELIOS. The paper is available at

modulator with self aligned junction reported

A consortium involving the universities of Heriot-Watt, Warwick, Surrey and Leeds have been awarded EPSRC funding of £1.43M to investigate single photon detectors in group IV materials. Professor Graham Reed is PI of the Surrey component and Professor Russell Gwilliam and Dr Goran Mashanovich are co-investigators.

epsrc research award for a uk consortium

Renzo Loiacono and co-workers from the University of Surrey, Intel Corporation and Numonyx have experimentally demonstrated laser erasable germanium implanted Bragg gratings in SOI. Bragg gratings are formed in a silicon waveguide by ion implantation induced amorphization, and are subsequently erased by a contained laser thermal treatment process. An extinction ratio up to 24dB has been demonstrated in transmission for the fabricated implanted Bragg gratings which can be selectively removed by UV pulsed laser annealing, enabling a new concept of laser erasable devices for integrated photonics. The paper is available at:

locally erasable bragg gratings in SOI waveguides fabricated

Dr David Thomson and Dr Frederic Gardes 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 (by Intel) with data transmission at 40Gbit/s and that had just a 1dB extinction ratio. 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. 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 work has recently been published in Optics Express and can be found at the following links:

40 gbit/s all silicon optical modulation with high extinction ratio

The group welcome Callum Littlejohns and Scott Reynolds, our new PhD students who will be working on efficient couplers and electronic/photonic integrated circuits. The have both recently graduated from the University of Surrey (Department of Electronic Engineering). Callum had the second highest average mark in the cohort and received prizes from Oclaro and IET for the best performance in the Optoelectronics module and for the best undergraduate project, respectively. Scott completed a professional training year at Visteon Engineering Services UK, working within the In Car Entertainment team helping to produce the entertainment system in Jaguar XJ. Upon graduating in 2011 he received the ECE prize for highest Professional Training grade on his stream. Scott's interests do not only reside within academia as he is a keen sportsman, captaining the University's Ultimate Frisbee team and playing for many clubs in the surrounding area.

callum and scott join the group

Recently, the group have published several interesting results including: 50 Gb/s depletion modulator in silicon, 40 Gb/s slow light modulator, modulation of absorption at 1.3 um in Ge/SiGe MQWs on silicon, novel (DE)MUX devices, modulation predictions for the mid-infrared, and athermal waveguides for the near-infrared. More information can be found on the links below:

50 Gb/s silicon optical modulator

High speed silicon modulators enhanced via slow light propagation

Modulation of absorption coefficient at 1.3 um in Ge/SiGe multiple quantum well heterostructures

Wavelength division (de)multiplexing based on waveguide mode dispersion

Modulation predictions for silicon over the 1-14 um wavelength range

Athermal waveguides for optical communication wavelengths

recent research highlights