Microstructured Fibre for Quantum Information

Lead Research Organisation: University of Bristol
Department Name: Electrical and Electronic Engineering

Abstract

This project focuses on the development of single- and multi-photon sources for quantum information applications based on photonic crystal fibres (PCFs). It brings together two internationally renowned UK research teams in order to design, build and test devices which are optimally tailored to this application.Recent developments in quantum optics have shed new light on the way we see information, communication and computation. No-longer are we limited to classical operations, but we can also harness the fundamental quantum nature of light to real-world uses. The most developed example of this is quantum cryptography; a way of exchanging cryptographic keys with provable security. Various groups, including ours, are now looking to go beyond quantum cryptography to perform multi-photon quantum logic and quantum communication experiments. Key resources for these experiments are sources of heralded single photons, pair photons and entangled pair photons and eventually multiple photons. There is currently a drive towards experiments in optical fibre, because of the inherent single spatial mode, ease of alignment and long transmission lengths possible for communication and teleportation experiments. Recently through discussions between the Bath and Bristol groups we realised that PCFs could be used as efficient single mode pair photon sources. Our combined knowledge of PCFs and the quantum information 'toolbox' has then led to the development of this proposal. We have already performed ground breaking preliminary experiments generating pair photons using off-the-shelf fibre originally designed for other applications. Here we are interested in engineering the ultimate performance from fibre sources of photon pairs and hope to produce the worlds first three photon source. This will allow us to perform world leading multiphoton experiments with quantum information applications in mind.
 
Description In this project we succeeded in building efficient quantum optical sources in fibre and performed the first experiments illustrating their usefulness for quantum information applications. This was done in collaboration with Bath University who were able to provide specially designed photonic crystal fibre samples that allowed us to optimise pair-photon sources in the visible ~500-700nm and near infrared region ~700-900nm, using a Ti:sapphire laser pump source. This has allowed the development of multiphoton quantum gate experiments and cluster state generation experiments.

All-fibre sources suitable for fibre quantum cryptography have also been developed fibres designed to produce (810-1550nm pairs) using a modelocked Yb fibre laser pump source.

Initial ambitions to develop three photon (GHZ state) sources went some way to showing third harmonic generation. However although some modal phase matched third harmonics were seen the efficiency was well below that needed to reverse the process to get 3-photon generation.
Exploitation Route We have continued this work and have added publications extending to 2015 which have arisen as a result of this work.
Sectors Digital/Communication/Information Technologies (including Software),Education,Electronics,Pharmaceuticals and Medical Biotechnology

 
Description European Research Council
Amount £2,250,000 (GBP)
Funding ID 247462 QUOWSS 
Organisation European Research Council (ERC) 
Sector Public
Country European Union (EU)
Start  
 
Description European Research Council
Amount £2,250,000 (GBP)
Funding ID 247462 QUOWSS 
Organisation European Research Council (ERC) 
Sector Public
Country European Union (EU)
Start 02/2010 
End 01/2015