Active Multiplexing of Spectrally Engineered Heralded Single Photons in an Integrated Fibre Architecture (eBook)

Dr Robert Francis-Jones received his PhD from the University of Bath in 2016 for his work on multiplexing high-purity heralded single photon sources under the supervision of Dr Peter Mosley, for which he received the Institute of Physics Quantum Electronics and Photonics Doctoral Thesis Prize 2017. His main research areas include the design and fabrication of photonic crystal fibres (PCF) for photon pair generation in PCF for use in heralded single photon sources, and quantum frequency translation of single photons from the visible to the infrared.  His other research interests include, numerical modelling of nonlinear optical processes such as four-wave mixing,  the development of field programmable gate array designs for photon counting and fast feed forward optical switching schemes and the development of antiresonant hollowcore optical fibres for quantum optics applications.

Supervisor’s Foreword 7
Abstract 9
Publication ListRobert J.A. Francis-Jones, Rowan A.Hoggarth and Peter J. Mosley, All-fibre multiplexed source of high-purity single photons, Optica, 3(11), pp. 1270–1273 (2016).Robert J.A. Francis-Jones and Peter J. Mosley, Characterisation of longitudinal variation in photonic crystal fibre, Optics Express, 24(22), pp. 24863–24845 (2016).Robert J.A. Francis-Jones and Peter J. Mosley, An all-fibre low-noise source of pure heralded single photons, In Preparation (2016).Robert J.A. Francis-Jones, Rowan A. Hoggarth and Peter J. Mosley, Spatial multiplexing of high-purity heralded single photons in an integrated fibre architecture, in CLEO: 2016, p. FTh1C.3, Optical Society of America (2016).Robert J.A. Francis-Jones and Peter J. Mosley, Experimental characterisation of longitudinal uniformity in photonic crystal fibre, in CLEO: 2016, p. STu4P.4, Optical Society of America (2016).Robert J.A. Francis-Jones and Peter J. Mosley, Temporal loop multiplexing: A resource efficient scheme for multiplexed photon-pair sources, arXiv e-prints arXiv:1503.06178 (2015).Peter J. Mosley, Itandehui Gris-SÃ nchez, James M.Stone, Robert J. A. Francis-Jones, Douglas J. Ashton, and Tim A. Birks, Characterizing the variation of propagation constants in multicore fibre, Optics Express, 22, pp. 25689–25699 (2014).Oliver J. Morris, Robert J.A. Francis-Jones, Keith G. Wilcox, Anne C. Tropper and Peter J. Mosley, Photon-pair generation in photonic crystal fibre with a 1.5 GHz modelocked VECSEL, Optics Communications, 327, pp. 39–44, Special issue on Nonlinear Quantum Photonics (2014).Robert J.A. Francis-Jones and Peter J. Mosley, Exploring the limits of multiplexed photon-pair sources for the preparation of pure single-photon states, arXiv e-prints arXiv:1409.1394 (2014). 10
Acknowledgements 11
Contents 12
Acronyms 15
Mathematical Variables 17
1 Introduction 20
1.1 What Is a Photon? 22
1.1.1 Indistinguishability and Hong-Ou-Mandel Interference 23
1.2 Methods of Single Photon Generation 26
1.2.1 Single Emitter Sources 26
1.2.2 Heralded Single Photon Sources 28
1.3 Multiplexing: A Route to Deterministic Operation 29
1.4 Thesis Outline 34
References 35
2 Photon Pair Generation via Four-Wave Mixing in Photonic Crystal Fibres 39
2.1 Overview 39
2.2 Photon Pair Generation in Photonic Crystal Fibres 41
2.3 Spectral Engineering of the Two-Photon State 44
2.4 Reduced State Spectral Purity: Schmidt Decomposition 49
2.5 Photon Number Statistics 50
2.5.1 Raman Scattering 50
2.5.2 Degree of Heralded Second Order Coherence 51
2.5.3 Degree of Marginal Second Order Coherence 52
References 53
3 Numerical Modelling of Multiplexed Photon Pair Sources 56
3.1 Overview 56
3.2 The Building Blocks 57
3.2.1 Pair Generation 57
3.2.2 Detection 58
3.2.3 Metrics and Measurements 60
3.3 Spatial Multiplexing 61
3.3.1 Simulation Results and Discussion 64
3.4 Temporal Loop Multiplexing 72
3.4.1 Simulation Results and Discussion 75
3.5 Conclusion 82
References 82
4 Design, Fabrication, and Characterisation of PCFs for Photon Pair Generation 84
4.1 Overview 84
4.2 Photonic Crystal Fibre Design and Fabrication 85
4.2.1 Simulation and Design 86
4.2.2 PCF Fabrication and Characterisation 89
4.3 Measuring the Joint Spectral Intensity Distribution 93
4.3.1 Stimulated Emission Tomography of FWM 94
4.4 The Effect of PCF Inhomogeneity on the Reduced State Purity 99
4.4.1 Numerical Reconstruction of Inhomogeneous PCFs 100
4.4.2 The Final Fibres 109
4.5 Conclusions 110
References 111
5 Construction of an Integrated Fibre Source of Heralded Single Photons 112
5.1 Overview 112
5.2 Photonic Bandgap Fibre Filter Design and Fabrication 113
5.3 Component Assembly and Splicing 117
5.3.1 PCF-SMF Splicing 118
5.3.2 PBGF-SMF Splicing 118
5.3.3 Assembly of the Photon Pair Source 122
5.4 Detection and Coincidence Counting Electronics 125
5.5 Optical Switch Integration 126
References 130
6 Characterisation of a Multiplexed Photon Pair Source 132
6.1 Overview 132
6.2 Characterisation of the Coincidence Count Rates 132
6.2.1 Coincidence Counting and Coincidence-to-Accidentals 134
6.2.2 Experimental Results: Coincidences and CAR 135
6.2.3 Experimental Results: Source 2 Noise Gating 141
6.3 Characterisation of the Second Order Coherence 143
6.3.1 Experimental Results: Marginal Second Order Coherence 144
6.3.2 Experimental Results: Heralded Second Order Coherence 150
6.4 Summary of Source Performance and Potential Improvements 152
6.5 Conclusions 156
References 156
7 Conclusion 158
7.1 Summary 158
7.2 Future Outlook 161
7.2.1 Photon Pair Generation in Fibres 161
7.2.2 Multiplexed Photon Pair Sources 162
References 163