QSE Junior Quantum Seminar - Tiff Brydges

Please join us for the Junior Quantum Seminar with Tiff Brydges from the Quantum Technologies Group at the Department of Applied Physics (University of Geneva) who will give the talk "Integrated Micro-Ring Resonators for Enabling Quantum Networks" on Tuesday April 15th from 9h30-11h.

PLEASE NOTE: The Junior Quantum Series are for gathering  the junior quantum community of master's students, PhDs and post-docs at EPFL, to create a non-judgmental space were scientific ideas can be shared between peers. This event is not for Professors or senior researchers. 

ABSTRACT:
A key component of quantum communication is the distribution of entanglement through networks. However, this comes with several challenges. One of the most significant is that direct transmission of quantum information between two nodes, via a standard fibre link, is unfeasible for transmission distances of more than a few hundreds of kilometres [1]. A solution is the ‘quantum repeater’ architecture. This distributes entanglement between two nodes via an intermediate repeater station [2], forming an elementary repeater link. Current state of the art experiments have recently implemented proof-of-principle, repeater-like networks with quantum memories [3]. However, such experiments often use highly complex photon sources, which is impractical when moving towards a realistically implementable and scalable quantum network. Integrated photonics is a promising solution to this problem, allowing large numbers of components to be packaged together in a compact and stable manner [4]. Interfacing sources with quantum memories based on atomic systems places strict requirements on the photon source, including the requirement for generation of narrow bandwidth photons, fast-frequency actuation for locking to the memory transition, and wavelength compatibility, with many atomic transitions being in the visible or NIR regimes. Integrated micro-ring resonators (MRRs) have already shown they are well-suited to the production of narrow-band photons, with bandwidths compatible with some rare-earth ion quantum memories [5, 6, 7], and the potential for generating photons with highly non-degenerate wavelengths [8]. This talk will showcase our recent work at the University of Geneva in addressing these challenges with integrated MRRs, so moving towards the development of integrated quantum nodes for elementary repeater links. Results from fast-frequency control of the integrated photonic MRRs will be presented, with a resulting locking bandwidth many times higher than achievable with the thermal locking schemes used previously [7]. To highlight the narrowband nature of our sources, and their suitability for use in quantum networks with quantum memories, recent entanglement visibility measurements will be presented. In addition, Hong-Ou-Mandel interference from two independent, narrow-band MRR photon sources will be shown, with quantum beat signatures [9] being seen due to the long photon coherence times.

[1] M. Krenn et al., Quantum Communication with Photons, pp. 455–482, Springer International Publishing (2016)
[2] N. Sangouard et al., Quantum repeaters based on atomic ensembles and linear optics, Rev. Mod. Phys., 83, pp. 33–80 (2011)
[3] D. Lago-Rivera et al., Telecom-heralded entanglement between multimode solid-state quantum memories, Nature, 594, pp. 37-40 (2021)
[4] S. Slussarenko & G. J. Pryde, Photonic quantum information processing: A concise review, Appl. Phys. Rev., 6(4), 041303 (2019)
[5] F. Samara et al., Entanglement swapping between independent and asynchronous integrated photon-pair sources, Quantum Sci. Technol., 6(4), (2021)
[6] M. Businger et al., Optical Spin-Wave Storage in a Solid-State Hybridized Electron-Nuclear Spin Ensemble, Phys. Rev. Lett., 124, 053606 (2020)
[7] T. Brydges et al., Integrated photon-pair source with monolithic piezoelectric frequency tunability, Phys. Rev. A, 107, 052602 (2023)
[8] X. Lu et al., Chip-integrated visible–telecom entangled photon pair source for quantum communication Nat. Phys, 15, 373-381 (2019)
[9] T. Legero et al., Quantum Beat of Two Single Photons Phys. Rev. Lett., 93, 070503 (2004)

BIO:
Originally from the UK, I did my undergraduate and Masters studies at the University of Oxford, specialising in the final year on quantum computing with integrated photonic platforms. In 2016 I moved to the University of Innsbruck in Austria to do my PhD under Rainer Blatt, where I worked on quantum computing with trapped ion platforms. Following this, in 2021 I came to the University of Geneva for a postdoc working on quantum networks. Since 2024 I hold an SNSF Ambizione fellowship at the University of Geneva, where I focus on interfacing integrated photonic platforms with quantum memories for quantum networks.​​​​​​​