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Title: Flexible precision timing instrumentation and quantum key distribution
Author: Nock , Richard William Raymond
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2013
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Time to Digital Conversion (TDC) is a fundamental building block of many applications, such as quantum information experiments, quantum key distribution, laser detection and ranging (LiDAR), bio-medical imaging, digital phase lock loops, and more. As of today, most timing instruments make use of analogue circuitry or application specific integrated circuits to time input events to picosecond resolution and bin size. As such solutions require programmable logic , to perform calibration and communication tasks, there would be a considerable cost and simplification gain obtained in implementing picosecond timing on the same programmable logic Integrated Circuit (IC). In addition to this, fully digital implementation would allow for such technology to enter broader markets. Numerous methods of implementing TDCs in programmable logic already exist. However, they are limited in bin size, linearity, accuracy or exhibit signi- . ficantly long dead times, due to the fixed structure of the Field Programmable Gate Array (FPGA) itself. This work demonstrates a novel ti~ing technique implemented within a low cost off the shelf FPGA that outperforms previously documented techniques in terms of bin size and linearity. A bin size of 1 ps, single shot precision of 17.11 ps , and a differential and integral. non linearity of < 1 has been demonstrated on a Spartan 6 LX75. The technique's performance is comparable to commercially available instruments costing in excess of an order of magnitude more. A flexible firmware and software defined timing platform has been developed, and four instruments have been demonstrated on it. A multi channel ('"'-'30 ps bin size) TDC, Time Correlated Single Photon Counter, coincidence counter and the aforementioned small bin size TDC have all been developed on a common low cost platform, exploiting the re-programmability of FPGAs. This allows for the functionality to be customised and changed at will, even remotely, as functionality is defined by the FPGA's bitfile and associated Personal Computer (PC) software. The use of such instruments is demonstrated, including hardware for two quantum key distribution systems (the Bristol free space system and the reference frame independent demonstration system), a LiDAR system, and in coincidence counting in quantum optics experiments.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available