Complex nanophotonic and plasmonic networks for ultrafast optical devices

Lead Research Organisation: University of Southampton
Department Name: School of Physics and Astronomy

Abstract

Photonic technologies are playing an increasingly important role in our society with revolutionary applications ranging from optical data storage to broadband fibre internet. As electronics and nanophotonics are rapidly converging toward one hybrid nanotechnology, important open challenges arise related to the routing and control of light in integrated optoelectronic circuits. In this project, a conceptually new approach toward reconfigurable and switchable optical circuits will be developed. We choose the widely-used silicon-based nanophotonics platform. Our new approach will be enabled by the integration of photonic waveguides with chalcogenide phase-change materials that are used in rewritable DVDs. Reversible optical writing of patterns into the phase-change layer will achieve reconfigurable devices for routing of optical signals on a chip.

We will take the concept of phase-change technology to the next level by exploiting the technology for studying light transport in fundamentally new types of nanophotonic devices inspired by mesoscopic physics. We will design two-dimensional photonic layers in which light is controlled by the coherent mixing of a number of possible light paths. The reconfigurable phase-change layer will be used as a wavefront shaper to send light through such photonic layers etched in the waveguide. Subsequently, a pattern of ultrafast light pulses will be projected onto the waveguide to produce an ultrafast modulation of the independent light paths. This pattern will be used to achieve ultrafast switching devices through a new process of ultrafast demixing, which is fundamentally different from conventional switching devices. These processes will be facilitated by the dramatic enhancement of the Kerr optical nonlinearity by the chalcogenide cladding, by the use of nanoplasmonic actuators, and through design of advanced nanostructures, such as photonic graphene, thereby exploiting the analogies of light with solid-state quantum electronics.

Our studies include the use of plasmonic elements as nanoscale actuators to control the chalcogenide light modulator. Conversively, we will investigate how the hybrid plasmonic-chalcogenide networks can be used to achieve optical memristors, one of the building blocks of neural architectures. Such optical elements would be a first step toward routing of signals in a brain-like manner, which could lead to radically new modes of distribution and processing of information.

Planned Impact

This proposal is aimed at generating impact by integrating three of the most promising emerging technologies: silicon photonics, phase-change materials, and plasmonics. We expect that combinations of these different elements will result in new types of devices. For example, the proposed chalcogenide phase-change devices can act as miniature reconfigurable circuitry. They can be directly connected to phase-change RAM memory functionalities to provide optical readout of data. Although we address here optically addressable phase-change devices, electronic read- and write-operations may be readily implemented. Plasmonics, the optical response resulting from collective oscillations of electrons in metal nanostructures, forms a natural bridge between photons and electrons. Plasmonically actuated photonic waveguides therefore hold promise for designing ultracompact devices for photon-electron integration.

The adaptation of concepts from the fields of quantum electronics and light scattering to silicon integrated photonics is motivated by scientific curiosity. These new concepts may however hold potential to generate disruptive new technology which may lead to increase in information capacity and fundamental new ways of controlling optical data, with the ultimate application of brain-inspired signal routing and processing.

Publications

10 25 50
 
Description Photonic chips made from silicon will play a major role in next generation optical networks for worldwide data traffic. The high refractive index of silicon makes optical structures the size of a fraction of the diameter of a human hair possible. Squeezing more and more optical structures for light distribution, modulation, detection and routing into smaller chip areas allows for higher data rates at lower fabrication costs. Those are qualities well sought after in a world with an exponentially growing demand for data.

As the complexity of optical chips increases, testing and characterizing such chips becomes more difficult. Light traveling in the chip is confined in the silicon, that is, it cannot be "seen" or measured from the outside.

Ultrafast photomodulation spectroscopy (UPMS) is a new method to find out at which time the light in the chip is at which position. UPMS uses ultraviolet laser pulses of femtosecond duration to change the refractive index of silicon in a tiny spot of the photonic chip. Monitoring the transmission of the chip while the refractive index is locally changed gives a precise picture of how the light flows through the chip. This allows testing pf all individual optical elements on the chip and making necessary changes in the design for a flawless chip operation. Because the changes in the refractive index of the silicon are fully reversible, this testing method is non-destructive and after testing, the chip can be used for its intended application.

UPMS is of interest for scientist designing complex photonic chips and might in coming years establish itself as the standard characterization tool in the scientific society, making photonic chips under development more reliable and bringing them into the market quicker. Additionally, it is fast and robust and has the potential to be used for industrial testing in the photonics industry.

In a series of experiments, we have used ultrafast pulses to study, control and alter the flow of light in integrated photonic structures. Results include the control of modes in integrated photonic cavities on silicon, where we have switched a cavity from a classical to a chaotic regime. We have developed an integrated spatial light modulator on silicon. Here, a pattern of local perturbations is projected onto the photonic chip, which is then used to steer the light.
Exploitation Route We would like to see our techniques to be converted into a mainstream characterisation tool for the integrated photonics industry / community. We are working together with the EPSRC Silicon Photonics for Future Systems Program where we have obtained a 1 year Innovation Grant to further develop wafer-scale testing. Also the methods of exploiting multimode complexity have to be implemented in actual devices. We are applying for follow-on funding in order to further pursue this direction.
Sectors Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Healthcare,Other

URL http://www.newelectronics.co.uk/article-images/144320/P24-25.pdf
 
Description We have developed a new photonic testing techique, which is being further developed with the EPSRC program on Silicon Photonics for Future System. The technique is currently attracting interest for companies such as Oclaro who are partners on the program grant.
First Year Of Impact 2016
Sector Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Electronics
Impact Types Societal

 
Description DSTL UK-France PhD studentship grant 2014-2018
Amount £146,552 (GBP)
Organisation Defence Science & Technology Laboratory (DSTL) 
Sector Public
Country United Kingdom
Start 10/2014 
End 09/2018
 
Description International Exchanges Scheme 2016
Amount £11,745 (GBP)
Funding ID IE160744 
Organisation The Royal Society 
Sector Academic/University
Country United Kingdom
Start 03/2017 
End 03/2019
 
Description Research Grant 2014-2015
Amount £15,000 (GBP)
Funding ID RG130863 
Organisation The Royal Society 
Sector Academic/University
Country United Kingdom
Start 03/2014 
End 02/2015
 
Description Silicon Photonics for Future Systems - Innovation Fund
Amount £31,000 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 03/2017 
End 05/2018
 
Description Collaboration with LP2N, Bordeaux 
Organisation Institute of Optics Bordeaux
Country France 
Sector Academic/University 
PI Contribution Experimental investigation of mode coupling in silicon photonic waveguides
Collaborator Contribution Numerical investigation of mode coupling in silicon photonic waveguides
Impact K. Vynck, N. J. Dinsdale, B. Chen, R. Bruck, A. Z. Khokhar, S. A. Reynolds, L. Crudgington, D. J. Thomson, G. T. Reed, P. Lalanne, O. L. Muskens, Ultrafast perturbation maps as a quantitative tool for testing of multi-port photonic devices, Arxiv:1802.06600 (2018); R. Bruck, K. Vynck, P. Lalanne, B. Mills, D. J. Thomson, G. Z. Mashanovich, G. T. Reed, O. L. Muskens, All-optical spatial light modulator for reconfigurable silicon photonic circuits, Optica 3, 396 - 402 (2016)
Start Year 2015
 
Description Collaboration with University of Eindhoven, the Netherlands 
Organisation Eindhoven University of Technology
Country Netherlands 
Sector Academic/University 
PI Contribution Access to optical characterisation laboratory
Collaborator Contribution Dedicated growth of semiconductor nanowire samples for optical experiments
Impact T. Strudley, T. Zehender, C. Blejean, E. P. A. M. Bakkers, O. L. Muskens, Mesoscopic light transport by very strong collective multiple scattering in nanowire mats, Nat. Photon. 7, 413-418 (2013)
Start Year 2010
 
Description Collaboration with University of Twente, the Netherlands 
Organisation University of Twente
Country Netherlands 
Sector Academic/University 
PI Contribution Access to experimental research equipment, collaborative exchange visit
Collaborator Contribution Access to experimental research equipment, collaborative exchange visit
Impact T. Strudley, D. Akbulut, W. L. Vos, A. Lagendijk, A. P. Mosk, O. L. Muskens, Observation of Intensity Statistics of Light Transmitted Through 3D Random Media, Optics Letters, 39, 6347-6350 (2014) D. Akbulut, T. Strudley, J. Bertolotti, A. Lagendijk, W. L. Vos, O. L. Muskens, A. P. Mosk, Optical transmission matrix measurements of disordered GaP nanowire mats reveal the dimensionless scattering strength, Physical Review Letters, submitted (2014)
Start Year 2012
 
Description Silicon Photonics Consortium 
Organisation Polytechnic University of Bari
Country Italy 
Sector Academic/University 
PI Contribution Spectroscopic characterization of samples provided by partners
Collaborator Contribution Access to integrated photonics chips fabricated by partners from Bari and Southampton; access to characterisation facilities Southampton Integrated Photonics Group
Impact R. Bruck, B. Mills, B. Troia, D. J. Thomson, F. Y. Gardes, Y. Hu, G. Z. Mashanovich, V. M. N. Passaro, G. T. Reed, O. L. Muskens, Device-level characterization of the flow of light in integrated photonic circuits using ultrafast photomodulation spectroscopy, Nature Photonics accepted 2014
Start Year 2014
 
Description Silicon Photonics Consortium 
Organisation University of Southampton
Country United Kingdom 
Sector Academic/University 
PI Contribution Spectroscopic characterization of samples provided by partners
Collaborator Contribution Access to integrated photonics chips fabricated by partners from Bari and Southampton; access to characterisation facilities Southampton Integrated Photonics Group
Impact R. Bruck, B. Mills, B. Troia, D. J. Thomson, F. Y. Gardes, Y. Hu, G. Z. Mashanovich, V. M. N. Passaro, G. T. Reed, O. L. Muskens, Device-level characterization of the flow of light in integrated photonic circuits using ultrafast photomodulation spectroscopy, Nature Photonics accepted 2014
Start Year 2014
 
Description Complex Nanophotonics Science Camp, 18-21 August, Cumberland Lodge (2013) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact In August 2013, the Complex Nanophotonics Science Camp, 'an unconventional gathering' took place in the Cumberland Lodge, Windsor Park. The event was organised by Dr Sapienza (Kings College), Dr Bertolorri (Exeter), Dr Gigan (EPCI / Insititute Langevin, Paris) and Dr Muskens (Southampton). During this event, around 60 early career researchers (strictly less than 10 years from obtaining their PhD) discussed about a range topics ranging from (bio-)imaging in complex media, photonic information technology, and advanced photonic materials. Evening discussions were held with expert panellists (Kosmas Tsakmakidis, Nature Materials; Ad Lagendijk, professor and opinion-maker; Timo Hannay, Digital Science/NPG; Kostas Repanas, A-Star Singapore) about a variety of topics related to scientific publishing, data sharing and visualization, and open innovation.

The event helped shaping a new community and brought together a next generation of scientists in an informal and stimulating setting which has raised much praise (see the www.sciencecamp.eu website for a podcast of the 2013 event).
Year(s) Of Engagement Activity 2013,2015
URL http://www.sciencecamp.eu