Advanced all-optical signal processing using quadratic nonlinearities

Lead Research Organisation: University of Southampton
Department Name: Optoelectronics Research Centre


With the advent of the Internet data traffic has rapidly over taken voice to become the dominant type of information transported by today's high speed optical communication networks. Moreover traffic is predicted to continue to grow at a phenomenal pace for the foreseeable future, driven by existing applications such as e-mail, e-commerce and video conferencing along with emerging applications such as telemedicine, virtual reality games and video-on-demand. In order to increase the capability and flexibility of optical networks to allow for new services and the next generation Internet, it will become increasingly more attractive, if not essential, to process the data signals within the optical layer. The nodes of these advanced telecom networks will thus require highly functional optical devices capable of seamlessly processing multiple signals in parallel at extremely high speeds (40 Gbit/s and beyond). The optical analogues of the modulators, switches and mixers used in electrical systems are thus required, dictating the need to use nonlinear optical effects.To date the majority of research into nonlinear optical devices has focussed on the use of optical fibre which posseses an ultrafast but unfortunately inherently low nonlinearity, or semiconductor materials which suffer from relatively low switching speeds. In this project we propose to investigate a different approach, based on the use of quadratic nonlinearities, which despite their many attractive properties, still remain the least explored option in the telecom area. To prove and leverage the full potential of quadratic nonlinearities in this field, we want to design and develop several compact, quadratic all-optical processing modules capable of operating at modest optical power levels and that are able to meet the stringent requirements of ultrahigh capacity telecom systems. To achieve this we will exploit the use of cascaded nonlinear effects in periodically poled lithium niobate waveguides. We shall also look to exploit various pulse shaping techniques, and the use of novel apodised nonlinear grating designs. It is to be appreciated that although telecoms is the main target-application to be considered within this project several of the device concepts developed should also be of use for other all-optical processing applications in fields such as metrology, spectroscopy, sensing, biology and medicine.


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Description We developed new ways of performing all-optical signal processing based on the use of waveguides made in lithium niobate. We used this technology to demonstrate functions such as wavelength conversion, phase conjugation and phase sensitive amplification - all of which are likely to become key functionalities in future optical networks. We firmly established Southampton as a world leader in optical signal processing through this grant.
Exploitation Route Japanese industry, e.g. NTT and Fujitsu, have followed our lead in this area and have established substantial programs on using lithium niobate within communications, achieving further outstanding results.
Sectors Digital/Communication/Information Technologies (including Software),Manufacturing, including Industrial Biotechology

Description EPSRC Responsive mode
Amount £588,248 (GBP)
Funding ID EP/J021970/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 09/2012 
End 10/2015
Description EU EURAMET Scheme
Amount € 121,464 (EUR)
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 11/2013 
End 11/2014
Description RAENG Fellowship (FRP)
Amount £350,000 (GBP)
Organisation Royal Academy of Engineering 
Sector Learned Society
Country United Kingdom
Start 10/2009 
End 10/2015
Description University of Southampton
Amount £35,000 (GBP)
Funding ID EPSRC Doctoral Prize Award - Dr Sheng Lui 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 07/2011 
End 06/2012
Description PPLN collaboration with KTH 
Organisation Royal Institute of Technology
Country Sweden 
Sector Academic/University 
PI Contribution Communication systems tests of novel optical processing functions in PPLN waveguides.
Collaborator Contribution Waveguide design and device modelling.
Impact See publication list.
Start Year 2008